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BREW-AIDER-CVE-2026-42271 (GHSA-V4P8-MG3P-G94G)

Vulnerability from osv_homebrew – Published: 2026-08-13 16:35 – Updated: 2026-09-09 23:40 – Source website
VLAI
Summary
LiteLLM: Authenticated command execution via MCP stdio test endpoints
Details

Impact

Two endpoints used to preview an MCP server before saving it — POST /mcp-rest/test/connection and POST /mcp-rest/test/tools/list — accepted a full server configuration in the request body, including the command, args, and env fields used by the stdio transport. When called with a stdio configuration, the endpoints attempted to connect, which spawned the supplied command as a subprocess on the proxy host with the privileges of the proxy process.

The endpoints were gated only by a valid proxy API key, with no role check. Any authenticated user — including holders of low-privilege internal-user keys — could therefore run arbitrary commands on the host.

Patches

Fixed in 1.83.7. Both test endpoints now require the PROXY_ADMIN role, bringing them into line with the save endpoint.

Workarounds

If upgrading is not immediately possible, developers should block POST /mcp-rest/test/connection and POST /mcp-rest/test/tools/list at their reverse proxy or API gateway.

Severity
8.8 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
8.7 (High)
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:N/SA:N
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "fix": null,
        "range_state": "affected",
        "resource": "litellm",
        "resource_purl": "pkg:pypi/litellm@1.81.10",
        "upstream_fixed_in": "1.83.7"
      },
      "package": {
        "ecosystem": "Homebrew",
        "name": "aider",
        "purl": "pkg:brew/aider"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "confidence": "high",
    "source": "matched",
    "strategy": "registry",
    "upstream_evidence": [
      {
        "ecosystem": "PyPI",
        "key": "pkg:pypi/litellm@1.81.10",
        "name": "litellm",
        "resource": "litellm",
        "strategy": "registry",
        "subject_version": "1.81.10"
      }
    ]
  },
  "details": "### Impact\n\nTwo endpoints used to preview an MCP server before saving it \u2014 `POST /mcp-rest/test/connection` and `POST /mcp-rest/test/tools/list` \u2014 accepted a full server configuration in the request body, including the `command`, `args`, and `env` fields used by the stdio transport. When called with a stdio configuration, the endpoints attempted to connect, which spawned the supplied command as a subprocess on the proxy host with the privileges of the proxy process.\n\nThe endpoints were gated only by a valid proxy API key, with no role check. Any authenticated user \u2014 including holders of low-privilege internal-user keys \u2014 could therefore run arbitrary commands on the host.\n\n### Patches\n\nFixed in **`1.83.7`**. Both test endpoints now require the `PROXY_ADMIN` role, bringing them into line with the save endpoint.\n\n### Workarounds\n\nIf upgrading is not immediately possible, developers should block `POST /mcp-rest/test/connection` and `POST /mcp-rest/test/tools/list` at their reverse proxy or API gateway.",
  "id": "BREW-aider-CVE-2026-42271",
  "modified": "2026-09-09T23:40:56Z",
  "published": "2026-08-13T16:35:12Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/BerriAI/litellm/security/advisories/GHSA-v4p8-mg3p-g94g"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42271"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/BerriAI/litellm"
    },
    {
      "type": "WEB",
      "url": "https://github.com/BerriAI/litellm/releases/tag/v1.83.7-stable"
    },
    {
      "type": "WEB",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-42271"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "LiteLLM: Authenticated command execution via MCP stdio test endpoints",
  "upstream": [
    "GHSA-v4p8-mg3p-g94g",
    "CVE-2026-42271",
    "PYSEC-2026-2599"
  ]
}



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