CVE-2026-42271 on CISA KEV

LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format. From version 1.74.2 to before version 1.83.7, 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 s

01What CISA says about this vulnerability

LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format. From version 1.74.2 to before version 1.83.7, 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…

02Required action — verbatim from CISA

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

03Notes & references

• github.com — https://github.com/BerriAI/litellm/releases/tag/v1.83.7-stable
• github.com — https://github.com/BerriAI/litellm/security/advisories/GHSA-v4p8-mg3p-g94g
• access.redhat.com — https://access.redhat.com/errata/RHSA-2026:27784
• access.redhat.com — https://access.redhat.com/errata/RHSA-2026:28960
• access.redhat.com — https://access.redhat.com/errata/RHSA-2026:30056
• access.redhat.com — https://access.redhat.com/security/cve/CVE-2026-42271
• bugzilla.redhat.com — https://bugzilla.redhat.com/show_bug.cgi?id=2467924
• security.access.redhat.com — https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42271.json
• www.cisa.gov — https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-…

04SARA's analyst layer — why this matters

This vulnerability is currently on the CISA KEV list, which CISA only adds CVEs to when there is reliable evidence of active exploitation in the wild. For federal civilian agencies, BOD 22-01 requires remediation by the due date above. For everyone else, KEV is the strongest "patch immediately" signal you can get from public threat intel.

05Affected products (summary)

No structured affected-product list available — see references below for vendor advisories.

06Detection

Open the Sigma generator with a pre-filled prompt for this CVE to draft a starting detection:

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