CVE-2025-53365

MCP Python SDK has Unhandled Exception in Streamable HTTP Transport ,Leading to Denial of Service

Description

The MCP Python SDK, called `mcp` on PyPI, is a Python implementation of the Model Context Protocol (MCP). Prior to version 1.10.0, if a client deliberately triggers an exception after establishing a streamable HTTP session, this can lead to an uncaught ClosedResourceError on the server side, causing the server to crash and requiring a restart to restore service. Impact may vary depending on the deployment conditions, and presence of infrastructure-level resilience measures. Version 1.10.0 contains a patch for the issue.

Category

8.7
CVSS
Severity: High
CVSS 4.0 •
EPSS 0.04%
Affected: modelcontextprotocol python-sdk
Published at:
Updated at:

References

Link Tags
https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-j975-95f5-7wqh
https://github.com/modelcontextprotocol/python-sdk/pull/967
https://github.com/modelcontextprotocol/python-sdk/commit/7b420656de48cfdb90b39eb582e60b6d55c2f891

Frequently Asked Questions

What is the severity of CVE-2025-53365?
CVE-2025-53365 has been scored as a high severity vulnerability.
How to fix CVE-2025-53365?
To fix CVE-2025-53365, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2025-53365 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2025-53365 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2025-53365?
CVE-2025-53365 affects modelcontextprotocol python-sdk.
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