The MCP Python SDK, called mcp on PyPI, is a Python implementation of the Model Context Protocol (MCP). Prior to 1.28.1, the deprecated mcp.server.websocket.websocket_server transport accepted WebSocket handshakes without applying Host or Origin header validation, leaving no SDK-level way to restrict which origins could connect to applications that exposed that transport. This issue is fixed in version 1.28.1.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
Present
Additional conditions required
Privileges Required
None
No privileges needed
User Interaction
Passive
Minimal interaction
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
None
No disruption
CVSS Vector v4.0
Weakness Type (CWE)
Vulnerable Products 1
| Configuration | From (including) | Up to (excluding) |
|---|---|---|
|
Lfprojects Mcp_Python_Sdk
cpe:2.3:a:lfprojects:mcp_python_sdk:*:*:*:*:*:*:*:*
|
— |
1.28.1
|
References 4
https://github.com/modelcontextprotocol/python-sdk/commit/777b8d06710c140e3606b…
security-advisories@github.com
https://github.com/modelcontextprotocol/python-sdk/pull/2992
security-advisories@github.com
https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.28.1
security-advisories@github.com
https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-vj7…
security-advisories@github.com