CVE-2026-59950
HIGHMCP Python SDK: WebSocket server transport does not support Host/Origin validation
Title source: cnaDescription
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.
References (4)
Core 4
Core References
X_Refsource_Confirm x_refsource_confirm
https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-vj7q-gjh5-988w
X_Refsource_Misc x_refsource_misc
https://github.com/modelcontextprotocol/python-sdk/pull/2992
X_Refsource_Misc x_refsource_misc
https://github.com/modelcontextprotocol/python-sdk/commit/777b8d06710c140e3606b0d4598e2aa48546c266
X_Refsource_Misc x_refsource_misc
https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.28.1
Scores
CVSS v3
8.1
EPSS
0.0015
EPSS Percentile
4.6%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
no
Technical Impact
total
Details
CWE
CWE-1385
CWE-346
Status
published
Products (3)
lfprojects/mcp_python_sdk
< 1.28.1
modelcontextprotocol/python-sdk
< 1.28.1
pypi/mcp
0 - 1.28.1PyPI
Published
Jul 15, 2026
Tracked Since
Jul 16, 2026