Vulnerability Monitor

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CVE-2025-53366

The MCP Python SDK, called `mcp` on PyPI, is a Python implementation of the Model Context Protocol (MCP). Prior to version 1.9.4, a validation error in the MCP SDK can cause an unhandled exception when processing malformed requests, resulting in service unavailability (500 errors) until manually restarted. Impact may vary depending on the deployment conditions, and presence of infrastructure-level resilience measures. Version 1.9.4 contains a patch for the issue.

Published

2025-07-04T22:15:22.300

Last Modified

2025-07-08T16:18:53.607

Status

Awaiting Analysis

Source

[email protected]

Severity

Weaknesses

Type: Primary
CWE-248

Affected Vendors & Products

References

https://github.com/modelcontextprotocol/python-sdk/commit/29c69e6a47d0104d0afcea6ac35e7ab02fde809a ([email protected])
https://github.com/modelcontextprotocol/python-sdk/pull/822 ([email protected])
https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-3qhf-m339-9g5v ([email protected])