High severity · published Jul 4, 2025
CVE-2025-53365
MCP Python SDK has Unhandled Exception in Streamable HTTP Transport ,Leading to Denial of Service
8.7
CVSS
0.4%
EPSS
No
On KEV
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.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 36% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
PY
python-sdk · modelcontextprotocol
< 1.10.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-53365
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-53365
github.com
https://github.com/modelcontextprotocol/python-sdk/commit/7b420656de48cfdb90b39eb582e60b6d55c2f891
github.com
https://github.com/modelcontextprotocol/python-sdk/pull/967
github.com
https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-j975-95f5-7wqh
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