LiteLLM MCP Authentication Bypass via OAuth2 Passthrough Fallback (CVE-2026-59822)
LiteLLM's MCP Streamable HTTP endpoint is vulnerable to an authentication bypass attack via OAuth2 passthrough fallback, allowing an unauthenticated attacker to establish an authenticated MCP session using an arbitrary Bearer token. This issue is fixed in version 1.84.0. A CVSS score of 8.8 indicates high severity.