Incorrect Authorization Affecting fastmcp package, versions [,2.14.2)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
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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Start learning- Snyk IDSNYK-PYTHON-FASTMCP-15674454
- published17 Mar 2026
- disclosed16 Mar 2026
- creditan7y
Introduced: 16 Mar 2026
NewCVE-2025-69196 (opens in a new tab)How to fix?
Upgrade fastmcp to version 2.14.2 or higher.
Overview
fastmcp is a The fast, Pythonic way to build MCP servers and clients.
Affected versions of this package are vulnerable to Incorrect Authorization due to improper handling of the resource parameter in the authorization and token request processes. An attacker can gain unauthorized access to resources on different MCP servers by reusing tokens issued for one server on another.