CVE-2025-53366 – mcp

Package

Manager: pip
Name: mcp
Vulnerable Version: >=0 <1.9.4

Severity

Level: High

CVSS v3.1: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:U/RC:C

CVSS v4.0: 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: 0.00057 pctl0.178

Details

MCP Python SDK vulnerability in the FastMCP Server causes validation error, leading to DoS 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. Thank you to Rich Harang for reporting this issue.

Metadata

Created: 2025-07-04T22:06:49Z
Modified: 2025-07-05T01:48:36Z
Source: https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/07/GHSA-3qhf-m339-9g5v/GHSA-3qhf-m339-9g5v.json
CWE IDs: ["CWE-248"]
Alternative ID: GHSA-3qhf-m339-9g5v
Finding: F140
Auto approve: 1