CVE-2025-53366
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BaseFortify

Publication date: 2025-07-04

Last updated on: 2025-07-08

Assigner: GitHub, Inc.

Description
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.
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Meta Information
Published
2025-07-04
Last Modified
2025-07-08
Generated
2026-05-07
AI Q&A
2025-07-05
EPSS Evaluated
2026-05-05
NVD
Affected Vendors & Products
Currently, no data is known.
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-248 An exception is thrown from a function, but it is not caught.
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AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability exists in the MCP Python SDK (mcp) prior to version 1.9.4, where a validation error when processing malformed requests can cause an unhandled exception. This leads to service unavailability, resulting in 500 errors until the service is manually restarted.


How can this vulnerability impact me? :

The vulnerability can cause the MCP SDK service to become unavailable due to unhandled exceptions triggered by malformed requests. This results in 500 errors and requires manual intervention to restart the service, potentially disrupting normal operations depending on deployment and infrastructure resilience.


What immediate steps should I take to mitigate this vulnerability?

Upgrade the MCP Python SDK to version 1.9.4 or later, which contains a patch for the validation error causing unhandled exceptions and service unavailability. Additionally, consider implementing infrastructure-level resilience measures to reduce impact until the upgrade can be applied.


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