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.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
High
Difficult to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
None
No data modification
Availability
None
No disruption
CVSS Vector v3.1
Weakness Type (CWE)
Vulnerable Products
modelcontextprotocol:python-sdk
References 7
https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-5h9…
https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-5h93-6whr-6q8j
https://github.com/modelcontextprotocol/python-sdk/pull/3397
https://github.com/modelcontextprotocol/python-sdk/pull/3397
https://github.com/modelcontextprotocol/python-sdk/pull/3448
https://github.com/modelcontextprotocol/python-sdk/pull/3448
https://github.com/modelcontextprotocol/python-sdk/commit/2106335745563b2321b8c…
https://github.com/modelcontextprotocol/python-sdk/commit/2106335745563b2321b8c73fef2c12903d00aa6e
https://github.com/modelcontextprotocol/python-sdk/commit/c6762e821c527925f0b61…
https://github.com/modelcontextprotocol/python-sdk/commit/c6762e821c527925f0b617db216d00fbd1d0bf99
https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.30.0
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/releases/tag/v2.2.0