Model Context Protocol Python SDK: Server bearer-token authentication accepts tokens issued for a different resource server

影響: pip:mcp >= 2.0.0, < 2.2.0 → 2.2.0, pip:mcp >= 1.10.0, < 1.30.0 → 1.30.0

In affected versions, the SDK's server-side bearer authentication had no way to check that a token was issued for your server (its audience). Where one authorization server issues tokens for several services, a valid token for another service was also accepted by your MCP server. Am I affected? Yes, if your HTTP server uses the SDK's bearer authentication (auth=AuthSettings(...) with token_verifier=), its authorization server also issues tokens for other services, and your TokenVerifier does no…

Read on GitHub Advisory Database

On 10/28/2026, 06:06 AM, GitHub Advisory Database published "Model Context Protocol Python SDK: Server bearer-token authentication accepts tokens issued for a different resource server" (type: Advisory). Severity is "Medium" (medium). Related technologies: Python. CVE: CVE-2026-116684.