CVE-2025-53365CWE-248

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

High · published July 4, 2025

CVSS v4.0
8.7
EPSS
0%
Percentile
35.1
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
8.7 · HIGH
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
EPSS
0.00419 · 35.1th percentile
Weakness
CWE-248 · Uncaught Exception
Published
2025-07-04T22:03Z
EPSS history
Timeline
  • 04 JUL 22:03Z
    MCP Python SDK has Unhandled Exception in Streamable HTTP Transport ,Leading to Denial of Service
    cvelistv5