SOURCE-LINKED INTELLIGENCE

GHSA-7488-6r32-c95q: LiteLLM: MCP Authentication Bypass via OAuth2 Passthrough Fallback

OSV AI package advisories · observation · Jul 22, 2026 · UTC

### Impact LiteLLM's MCP Streamable HTTP endpoint could allow an unauthenticated attacker to establish an authenticated MCP session using an arbitrary Bearer token. The MCP auth handler supported OAuth2 passthrough for upstream MCP servers, but the fallback path could replace failed LiteLLM key validation with an empty `UserAPIKeyAuth()` object. This allowed requests with a fabricated `Authorization` header to reach MCP tooling without a valid LiteLLM key. An attacker could use this to list and call configured MCP tools and access connected services exposed through MCP. ### Patches The issue i

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recordType: vulnerability
status: active
evidenceStatus: reported
region: Global

Evidence & attribution

OSV AI package advisories · 2026-07-22T22:38:33.000Z
OSV AI package advisories · 2026-07-23T11:41:48.668Z

First collected: 2026-09-20T23:41:51.992Z. This is not the publication date.