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.
Fix
Nothing published yet: no patch, vendor advisory or mitigation reference on NVD, no vendor advisory in the News for this CVE, not in CISA's KEV, no fixed package version. BaselineWatch does not guess at one.
Change history 4
- StatusPublished → Awaiting AnalysisNVD modified 2026-10-28 15:21
- StatusReceived → PublishedNVD modified 2026-10-27 19:12
- StatusPublished → ReceivedNVD modified 2026-10-27 20:17
- First seenCVSS 6.8 · modelcontextprotocolNVD modified 2026-10-27 19:12
Affected (CPE criteria) 0
NVD has not attached CPE configurations yet.
References 7
- https://github.com/modelcontextprotocol/python-sdk/commit/0c9136841ff092987a20700ff9c2c9789bda2f40
- https://github.com/modelcontextprotocol/python-sdk/commit/8c2fa6eabacde869d75568e33b9d466b58c2f512
- https://github.com/modelcontextprotocol/python-sdk/pull/3447
- https://github.com/modelcontextprotocol/python-sdk/pull/3451
- https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.30.0
- https://github.com/modelcontextprotocol/python-sdk/releases/tag/v2.2.0
- https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-w4fh-qvv9-3v23