{"id":"CVE-2026-116685","published":"2026-10-27T20:17:13.493","lastModified":"2026-10-27T20:17:13.493","description":"The Model Context Protocol Python SDK is the official Python SDK for Model Context Protocol servers and clients. From 1.8.0 until 1.30.0 and 2.2.0, streamable_http_client, streamablehttp_client, sse_client, ClientSessionGroup, OAuth, and create_mcp_http_client client paths enable follow_redirects and follow redirects to a different origin, forwarding caller-supplied custom credential headers and, for 307 or 308 responses, the request body. An attacker who can influence a trusted endpoint's redirect destination can receive that material. This issue is fixed in versions 1.30.0 and 2.2.0.","cvssScore":5.9,"cvssSeverity":"MEDIUM","cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","cwes":["CWE-200"],"vendors":[],"products":[],"references":[{"url":"https://github.com/modelcontextprotocol/python-sdk/commit/2106335745563b2321b8c73fef2c12903d00aa6e","tags":[]},{"url":"https://github.com/modelcontextprotocol/python-sdk/commit/c6762e821c527925f0b617db216d00fbd1d0bf99","tags":[]},{"url":"https://github.com/modelcontextprotocol/python-sdk/pull/3397","tags":[]},{"url":"https://github.com/modelcontextprotocol/python-sdk/pull/3448","tags":[]},{"url":"https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.30.0","tags":[]},{"url":"https://github.com/modelcontextprotocol/python-sdk/releases/tag/v2.2.0","tags":[]},{"url":"https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-5h93-6whr-6q8j","tags":[]}],"exploitRefs":[{"url":"https://github.com/modelcontextprotocol/python-sdk/commit/2106335745563b2321b8c73fef2c12903d00aa6e","tags":[]},{"url":"https://github.com/modelcontextprotocol/python-sdk/commit/c6762e821c527925f0b617db216d00fbd1d0bf99","tags":[]},{"url":"https://github.com/modelcontextprotocol/python-sdk/pull/3397","tags":[]},{"url":"https://github.com/modelcontextprotocol/python-sdk/pull/3448","tags":[]},{"url":"https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.30.0","tags":[]},{"url":"https://github.com/modelcontextprotocol/python-sdk/releases/tag/v2.2.0","tags":[]},{"url":"https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-5h93-6whr-6q8j","tags":[]}],"hasPoc":true,"ai":null}