{"id":"CVE-2026-116684","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-116684","summary":"The Model Context Protocol Python SDK is the official Python SDK for Model Context Protocol servers and clients. From 1.10.0 until 1.30.0 and 2.2.0, server-side bearer authentication…","details":"The Model Context Protocol Python SDK is the official Python SDK for Model Context Protocol servers and clients. From 1.10.0 until 1.30.0 and 2.2.0, server-side bearer authentication configured through AuthSettings with token_verifier accepts a valid token issued for another service when the authorization server serves multiple resources and the TokenVerifier does not independently validate the aud audience. This resource-confusion flaw lets a token holder authenticate to the wrong MCP server and exercise that token's resulting access. This issue is fixed in versions 1.30.0 and 2.2.0.","published":"2026-10-27T20:17:13.307","modified":"2026-10-27T20:17:13.307","cvss":{"score":6.8,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":{"url":"https://github.com/modelcontextprotocol/python-sdk/commit/0c9136841ff092987a20700ff9c2c9789bda2f40","label":"modelcontextprotocol/python-sdk@0c91368"},"references":[{"type":"WEB","url":"https://github.com/modelcontextprotocol/python-sdk/commit/0c9136841ff092987a20700ff9c2c9789bda2f40"},{"type":"WEB","url":"https://github.com/modelcontextprotocol/python-sdk/commit/8c2fa6eabacde869d75568e33b9d466b58c2f512"},{"type":"WEB","url":"https://github.com/modelcontextprotocol/python-sdk/pull/3447"},{"type":"WEB","url":"https://github.com/modelcontextprotocol/python-sdk/pull/3451"},{"type":"WEB","url":"https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.30.0"},{"type":"WEB","url":"https://github.com/modelcontextprotocol/python-sdk/releases/tag/v2.2.0"},{"type":"WEB","url":"https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-w4fh-qvv9-3v23"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-10-27T20:17:13.307"}}