Vulnerability-Lookup

CVE-2025-59155 (GCVE-0-2025-59155)

Vulnerability from cvelistv5 – Published: 2025-09-15 16:56 – Updated: 2025-09-15 17:30

Title

hackmd-mcp server-side request forgery in HTTP transport mode

Summary

hackmd-mcp is a Model Context Protocol server for integrating HackMD's note-taking platform with AI assistants. From 1.4.0 to before 1.5.0, hackmd-mcp contains a server-side request forgery (SSRF) vulnerability when the server is run in HTTP transport mode. Arbitrary hackmdApiUrl values supplied via the Hackmd-Api-Url HTTP header or a base64-encoded JSON query parameter are accepted without validation, allowing attackers to redirect outbound API requests to internal network services, access internal endpoints, perform network reconnaissance, and bypass network access controls. The stdio transport mode is not affected because it only accepts stdio requests. The issue is fixed in version 1.5.0, which enforces allowed endpoints and supports the ALLOWED_HACKMD_API_URLS environment variable. Users should update to 1.5.0 or later or apply documented mitigations such as switching to stdio mode, restricting outbound network access, or filtering the Hackmd-Api-Url header and related query parameter via a reverse proxy.

Severity

6.9 (Medium)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2025-09-15 17:30 UTC

CWE

CWE-918 - Server-Side Request Forgery (SSRF)

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 8017 records in the last 180 days details

References

2 references

URL	Tags
https://github.com/yuna0x0/hackmd-mcp/security/ad…	x_refsource_CONFIRM
https://github.com/yuna0x0/hackmd-mcp/commit/4393…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
yuna0x0	hackmd-mcp	Affected: >= 1.4.0, < 1.5.0	guessed

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2025-59155

Vulnerability from fkie_nvd - Published: 2025-09-15 17:15 - Updated: 2026-06-17 09:45

Severity

6.9 (Medium) - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/yuna0x0/hackmd-mcp/commit/43936c78a5bb3dedc74e8f080607a1125caa8c13
	security-advisories@github.com	https://github.com/yuna0x0/hackmd-mcp/security/advisories/GHSA-g5cg-6c7v-mmpw

Impacted products

	Vendor	Product	Version

JSON

To clipboard

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    {
      "affectedData": [
        {
          "product": "hackmd-mcp",
          "vendor": "yuna0x0",
          "versions": [
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  "lastModified": "2026-06-17T09:45:38.303",
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GHSA-G5CG-6C7V-MMPW

Vulnerability from github – Published: 2025-09-15 20:37 – Updated: 2025-09-15 20:37

Summary

HackMD MCP Server has Server-Side Request Forgery (SSRF) vulnerability

Details

Impact

A Server-Side Request Forgery (SSRF) vulnerability that affects all users running the HackMD MCP server in HTTP mode. Attackers could exploit this vulnerability by passing arbitrary hackmdApiUrl values through HTTP headers (Hackmd-Api-Url) or base64-encoded JSON query parameters. This allows malicious users to:

Redirect API calls to internal network services
Potentially access sensitive internal endpoints
Perform network reconnaissance through the server
Bypass network access controls

The vulnerability affects the HTTP transport mode specifically - stdio mode is not impacted as it only accepts requests from stdio.

Patches

The vulnerability has been patched in version 1.5.0. Users should:

Update to the latest version of the HackMD MCP server
Set the ALLOWED_HACKMD_API_URLS environment variable to restrict allowed HackMD API endpoints
If not set, the server will default to only allowing the official HackMD API URL (https://api.hackmd.io/v1)

Example configuration:

ALLOWED_HACKMD_API_URLS=https://api.hackmd.io/v1,https://your-hackmd-instance.com/api/v1

Workarounds

Users can mitigate this vulnerability without upgrading by:

Use stdio mode instead of HTTP mode: Set TRANSPORT=stdio or remove the TRANSPORT environment variable to disable HTTP mode entirely
Network-level restrictions: Use firewall rules or network policies to restrict outbound connections from the server
Reverse proxy filtering: Place the MCP server behind a reverse proxy that validates and filters both the Hackmd-Api-Url header and the base64-encoded JSON config query parameter to prevent malicious hackmdApiUrl values

References

Severity

6.9 (Medium)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N

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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "hackmd-mcp"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.4.0"
            },
            {
              "fixed": "1.5.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-59155"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-09-15T20:37:46Z",
    "nvd_published_at": "2025-09-15T17:15:36Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\n\nA Server-Side Request Forgery (SSRF) vulnerability that affects all users running the HackMD MCP server in HTTP mode. Attackers could exploit this vulnerability by passing arbitrary `hackmdApiUrl` values through HTTP headers (`Hackmd-Api-Url`) or base64-encoded JSON query parameters. This allows malicious users to:\n\n- Redirect API calls to internal network services\n- Potentially access sensitive internal endpoints\n- Perform network reconnaissance through the server\n- Bypass network access controls\n\nThe vulnerability affects the HTTP transport mode specifically - stdio mode is not impacted as it only accepts requests from stdio.\n\n### Patches\n\nThe vulnerability has been patched in version `1.5.0`. Users should:\n\n1. Update to the latest version of the HackMD MCP server\n2. Set the `ALLOWED_HACKMD_API_URLS` environment variable to restrict allowed HackMD API endpoints\n3. If not set, the server will default to only allowing the official HackMD API URL (`https://api.hackmd.io/v1`)\n\nExample configuration:\n```\nALLOWED_HACKMD_API_URLS=https://api.hackmd.io/v1,https://your-hackmd-instance.com/api/v1\n```\n\n### Workarounds\n\nUsers can mitigate this vulnerability without upgrading by:\n\n1. **Use stdio mode instead of HTTP mode**: Set `TRANSPORT=stdio` or remove the `TRANSPORT` environment variable to disable HTTP mode entirely\n2. **Network-level restrictions**: Use firewall rules or network policies to restrict outbound connections from the server\n3. **Reverse proxy filtering**: Place the MCP server behind a reverse proxy that validates and filters both the `Hackmd-Api-Url` header and the base64-encoded JSON `config` query parameter to prevent malicious `hackmdApiUrl` values\n\n### References\n\n- [OWASP Server-Side Request Forgery Prevention Cheat Sheet](https://cheatsheetseries.owasp.org/cheatsheets/Server_Side_Request_Forgery_Prevention_Cheat_Sheet.html)\n- [HackMD MCP Server Documentation](https://github.com/yuna0x0/hackmd-mcp)",
  "id": "GHSA-g5cg-6c7v-mmpw",
  "modified": "2025-09-15T20:37:46Z",
  "published": "2025-09-15T20:37:46Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/yuna0x0/hackmd-mcp/security/advisories/GHSA-g5cg-6c7v-mmpw"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-59155"
    },
    {
      "type": "WEB",
      "url": "https://github.com/yuna0x0/hackmd-mcp/commit/43936c78a5bb3dedc74e8f080607a1125caa8c13"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/yuna0x0/hackmd-mcp"
    },
    {
      "type": "WEB",
      "url": "https://github.com/yuna0x0/hackmd-mcp/releases/tag/v1.5.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "HackMD MCP Server has Server-Side Request Forgery (SSRF) vulnerability"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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Action not permitted

CVE-2025-59155 (GCVE-0-2025-59155)

FKIE_CVE-2025-59155

GHSA-G5CG-6C7V-MMPW

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