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TI-2025-42650 Aliases CVE-2025-69196GHSA-5h2m-4q8j-pqpj

FastMCP OAuth Proxy token reuse across MCP servers

Priority HIGH 66CWE-863Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Active
Attack complexity
High
Attack requirements
None
Impact type
Security bypass
Confidentiality · integrity · availability
High · High · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-863.

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.0038 32nd percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed fastmcp (jlowin): 2.14.2fastmcp (PyPI): 2.14.2Red Hat: 1 advisory

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
jlowinfastmcpbefore 2.14.22.14.2Patch availableCNA
—fastmcp (PyPI)before 2.14.22.14.2Patch availableGHSA-5h2m-4q8j-pqpj
  • fastmcp Vendorjlowin Affected before 2.14.2 Fixed in 2.14.2 Patch available CNA
  • fastmcp (PyPI) Vendor— Affected before 2.14.2 Fixed in 2.14.2 Patch available GHSA-5h2m-4q8j-pqpj

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:jlowin:fastmcp:*:*:*:*:*:*:*:*before 2.14.2Vulnerablejlowin
  • cpe:2.3:a:jlowin:fastmcp:*:*:*:*:*:*:*:* Versions before 2.14.2 Vulnerable ·jlowin

Remediation

  • Fix · CNA fastmcp (jlowin) Fixed in 2.14.2
  • Fix · GHSA-5h2m-4q8j-pqpj fastmcp (PyPI) Fixed in 2.14.2 Advisory →

Red Hat 1 advisory

  • RHSA-2026:36350 Released 2026-07-07 · Red Hat rating Important
    satellite/foreman-mcp-server-rhel9 container image available as a Technology Preview
    • Red Hat Satellite 6.18 registry.redhat.io/satellite/foreman-mcp-server-rhel9

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Satellite 6.18Fixed RHSA-2026:36350
Not affected: 2 products
  • Red Hat Developer Hub 1
  • Red Hat OpenShift AI (RHOAI)

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-69196
  2. 2026-10-03 Alias added: GHSA-5h2m-4q8j-pqpj
  3. 2026-10-27 Affected versions changed · Red Hat

References

Exploit 1

Advisory 1

Other 1

  • TI-2026-25332 FastMCP OpenAPI Provider has an SSRF & Path Traversal Vulnerability CVSS 4.0CRITICAL 10.0
  • TI-2026-21575 FastMCP: Missing Consent Verification in OAuth Proxy Callback Facilitates Confused Deputy Vulnerabilities CVSS 4.0HIGH 8.2
  • TI-2025-39774 FastMCP has a Command Injection vulnerability - Gemini CLI CVSS 3.1HIGH 7.8
  • TI-2025-38984 FastMCP vulnerable to windows command injection in FastMCP Cursor installer via server_name CVSS 4.0MEDIUM 5.4
  • TI-2025-38983 FastMCP vulnerable to reflected XSS in client's callback page CVSS 4.0MEDIUM 5.3

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences