CVE-2026-42203

Summary

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.

Affected Software

Weaknesses

• CWE-1336: CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine

ADP Enrichment

CISA ADP Vulnrichment

• SSVC:
• Exploitation: none
  • Automatable: no
  • Technical Impact: total

litellm: LiteLLM: Arbitrary code execution via unsandboxed prompt templates

Additional References

• https://access.redhat.com/security/cve/CVE-2026-42203
• https://bugzilla.redhat.com/show_bug.cgi?id=2467917
• https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42203.json

References

• https://github.com/BerriAI/litellm/security/advisories/GHSA-xqmj-j6mv-4862
• https://github.com/BerriAI/litellm/releases/tag/v1.83.7-stable

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