CVE-2025-53365 HIGH

CVE-2025-53365: MCP Python SDK has Unhandled Exception in Streamable HTTP Transport ,Leading to Denial of Service

Vendor Modelcontextprotocol

Product python-sdk

Weakness CWE-248

Published July 4, 2025

Last update July 8, 2025

View on NVD All CVEs

CVSS base score

8.7/10

Attack vector Network

Attack complexity Low

Privileges required None

User interaction None

Confidentiality —

Integrity —

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

What the vulnerability does

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.

Key dates

Disclosure timeline

July 4, 2025 CVE published

July 8, 2025 Record updated