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.
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 → DeferredNVD modified 2026-10-28 15:24
- StatusReceived → PublishedNVD modified 2026-10-27 19:26
- StatusPublished → ReceivedNVD modified 2026-10-27 20:17
- First seenCVSS 5.9 · modelcontextprotocolNVD modified 2026-10-27 19:26
Affected (CPE criteria) 0
NVD has not attached CPE configurations yet.
References 7
- https://github.com/modelcontextprotocol/python-sdk/commit/2106335745563b2321b8c73fef2c12903d00aa6e
- https://github.com/modelcontextprotocol/python-sdk/commit/c6762e821c527925f0b617db216d00fbd1d0bf99
- https://github.com/modelcontextprotocol/python-sdk/pull/3397
- https://github.com/modelcontextprotocol/python-sdk/pull/3448
- 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-5h93-6whr-6q8j