Uncaught Exception Affecting mcp package, versions [,1.9.4)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PYTHON-MCP-10734137
- published14 Jul 2025
- disclosed4 Jul 2025
- creditRich Harang
Introduced: 4 Jul 2025
NewCVE-2025-53366 (opens in a new tab)How to fix?
Upgrade mcp to version 1.9.4 or higher.
Overview
mcp is a Model Context Protocol SDK
Affected versions of this package are vulnerable to Uncaught Exception due to improper validation in the FastMCP Server process. An attacker can cause the service to become unavailable by sending malformed requests that trigger unhandled exceptions, resulting in repeated 500 errors and requiring manual intervention to restore normal operation.