CVE-2025-69196

Summary

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.

Affected Software

Weaknesses

• CWE-863: CWE-863: Incorrect Authorization

ADP Enrichment

CISA ADP Vulnrichment

• SSVC:
• Exploitation: poc
  • Automatable: no
  • Technical Impact: partial

fastmcp: FastMCP: Improper token issuance due to incorrect resource parameter handling

Additional References

• https://access.redhat.com/security/cve/CVE-2025-69196
• https://bugzilla.redhat.com/show_bug.cgi?id=2448179
• https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-69196.json

References

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

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