{"id":"CVE-2026-116684","revision":null,"records":[{"revision":"bf575f678ba3408692e25575529d6ec2","observedAt":"2026-10-27T20:45:55.474+00:00","statement":{"source":"cve-program","id":"CVE-2026-116684","aliases":[],"title":"Model Context Protocol Python SDK: Server bearer-token authentication accepts tokens issued for a different resource server","description":"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.","state":0,"publishedAt":"2026-10-27T19:12:24.255+00:00","modifiedAt":"2026-10-27T19:12:24.255+00:00","affected":[{"ecosystem":"Vendor product","name":"python-sdk","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"modelcontextprotocol\",\n                    \"product\": \"python-sdk\",\n                    \"versions\": [\n                        {\n                            \"version\": \">= 1.10.0, < 1.30.0\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \">= 2.0.0, < 2.2.0\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N","score":6.8,"severity":"MEDIUM"}],"references":["https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-w4fh-qvv9-3v23","https://github.com/modelcontextprotocol/python-sdk/pull/3447","https://github.com/modelcontextprotocol/python-sdk/pull/3451","https://github.com/modelcontextprotocol/python-sdk/commit/0c9136841ff092987a20700ff9c2c9789bda2f40","https://github.com/modelcontextprotocol/python-sdk/commit/8c2fa6eabacde869d75568e33b9d466b58c2f512","https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.30.0","https://github.com/modelcontextprotocol/python-sdk/releases/tag/v2.2.0"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-116684","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-116684","identifiers":["CVE-2026-116684"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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Not a global EPSS backfill.","generation":"2026-10-31T20:04:57.5651168+00:00","complete":true,"records":1094,"lastAttemptAt":"2026-10-31T20:04:57.5651168+00:00","lastSuccessAt":"2026-10-31T20:04:57.7280158+00:00","error":null,"lastVerifiedAt":"2026-10-31T20:04:57.728016+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"nvd","scope":"Rolling NVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. Not a global NVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-a558c2e000674838b5341fe81ce273de","complete":false,"records":13580,"lastAttemptAt":"2026-10-31T20:05:02.8072159+00:00","lastSuccessAt":"2026-10-31T19:05:21.516+00:00","error":"1 identifier lookups failed; latest failures include HTTP 503. 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