Vulnerability Description
LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format. From version 1.80.5 to before version 1.83.7, the POST /prompts/test endpoint accepted user-supplied prompt templates and rendered them without sandboxing. A crafted template could run arbitrary code inside the LiteLLM Proxy process. The endpoint only checks that the caller presents a valid proxy API key, so any authenticated user could reach it. Depending on how the proxy is deployed, this could expose secrets in the process environment (such as provider API keys or database credentials) and allow commands to be run on the host. This issue has been patched in version 1.83.7.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Litellm | Litellm | >= 1.80.5, < 1.83.7 |
Related Weaknesses (CWE)
References
- https://github.com/BerriAI/litellm/releases/tag/v1.83.7-stableProductRelease Notes
- https://github.com/BerriAI/litellm/security/advisories/GHSA-xqmj-j6mv-4862MitigationPatchVendor Advisory
FAQ
What is CVE-2026-42203?
CVE-2026-42203 is a vulnerability with a CVSS score of 8.8 (HIGH). LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format. From version 1.80.5 to before version 1.83.7, the POST /prompts/test endpoint accepted user-supplied prompt templa...
How severe is CVE-2026-42203?
CVE-2026-42203 has been rated HIGH with a CVSS base score of 8.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-42203?
Check the references section above for vendor advisories and patch information. Affected products include: Litellm Litellm.