Source: python-mcp X-Debbugs-CC: [email protected] Severity: grave Tags: security
Hi, The following vulnerability was published for python-mcp. CVE-2026-109527[0]: | The Model Context Protocol Python SDK is the official Python SDK for | Model Context Protocol servers and clients. In mcp versions before | 1.29.1 and from 2.0.0a1 through 2.0.1, the Streamable HTTP session | manager, SSE message endpoint, and OAuth authorization-server routes | buffer complete HTTP request bodies without enforcing a maximum | size. An unauthenticated remote client able to reach an affected | endpoint can send a large declared or streamed request body that | consumes multiple times the body size in process memory and can | repeatedly exhaust memory or terminate the server. Stdio-only | servers and deployments with an effective upstream request-size | limit are not affected, and applications that use | StreamableHTTPServerTransport directly remain responsible for | enforcing their own limit. The standard SDK server applications and | session managers are fixed in versions 1.29.1 and 2.1.0. https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-fmmv-w9g8-j3gc https://github.com/modelcontextprotocol/python-sdk/commit/4dc224fab201bdef2fd5a065976b7ca31420187c (v1.29.1) https://github.com/modelcontextprotocol/python-sdk/commit/5f0b6af9f2b0aad3be3ba5cbfe80a9e4ea32e189 (v1.29.0) If you fix the vulnerability please also make sure to include the CVE (Common Vulnerabilities & Exposures) id in your changelog entry. For further information see: [0] https://security-tracker.debian.org/tracker/CVE-2026-109527 https://www.cve.org/CVERecord?id=CVE-2026-109527 Please adjust the affected versions in the BTS as needed.
