CVE-2025-69196

FastMCP OAuth Proxy token reuse across MCP servers

CVSS 7.4 HIGHEPSS 0.3%CWE-863

Vexday Risk Score

21Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 7.4EPSS 0.3%KEV nãoPoC —Nuclei —Metasploit —Patch —

Lifecycle

16 Mar 2026Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

FastMCP is the standard framework for building MCP applications. Prior to version 2.14.2, the server does not properly respect the resource parameter submitted by the client in the authorization and token request. Instead of issuing the token explicitly for the MCP server, the token is issued for the base_url passed to the OAuthProxy during initialization. This issue has been patched 2.14.2.

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

Affected products

jlowin · fastmcp

Want to know if your infrastructure is exposed to this?

Talk to TrueHacking →

References

https://github.com/PrefectHQ/fastmcp/security/advisories/GHSA-5h2m-4q8j-pqpj