CVE Catalog

CVE-2026-59822

HighCVSS 8.2
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.52%

42th percentile - higher than 42% of all known CVEs

Summary

LiteLLM before version 1.84.0 has a vulnerability in the MCP Streamable HTTP endpoint that allows an unauthenticated attacker to bypass LiteLLM key validation using a crafted Authorization header. The attacker can exploit the OAuth2 passthrough fallback path to replace failed key validation with an empty UserAPIKeyAuth() object, allowing requests to reach MCP tooling without a valid key.

Risk Assessment

The risk is unauthorized access to MCP tooling, potentially leading to data leakage, unauthorized use of AI models, or other resources protected by LiteLLM.

Recommendation

Immediately upgrade LiteLLM to version 1.84.0 or later, which contains the fix for this vulnerability.

Other vulnerabilities in LiteLLM

See all
Original NVD description (English source)

LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format. Prior to 1.84.0, LiteLLM's MCP Streamable HTTP endpoint allowed an unauthenticated attacker to use a fabricated Authorization header to trigger an OAuth2 passthrough fallback path that replaced failed LiteLLM key validation with an empty UserAPIKeyAuth() object, allowing requests to reach MCP tooling without a valid LiteLLM key. This issue is fixed in version 1.84.0.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS