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CVE-2025-53366
Good to know:
Date: July 4, 2025
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.
Severity Score
Related Resources (7)
Severity Score
Weakness Type (CWE)
Uncaught Exception
CWE-248Top Fix
Upgrade Version
Upgrade to version mcp - 1.9.4;mcp - 1.9.4;https://github.com/modelcontextprotocol/python-sdk.git - v1.9.4
CVSS v3.1
| Base Score: |
|
|---|---|
| Attack Vector (AV): | NETWORK |
| Attack Complexity (AC): | LOW |
| Privileges Required (PR): | NONE |
| User Interaction (UI): | NONE |
| Scope (S): | UNCHANGED |
| Confidentiality (C): | NONE |
| Integrity (I): | NONE |
| Availability (A): | HIGH |