CVE-2025-69196CWE-863

FastMCP OAuth Proxy token reuse across MCP servers

High · published March 16, 2026

CVSS v4.0
7.4
EPSS
0%
Percentile
29.9
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
7.4 · HIGH
Vector
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
EPSS
0.00372 · 29.9th percentile
Weakness
CWE-863 · Incorrect Authorization
Published
2026-03-16T18:07Z
EPSS history
Timeline
  • 16 MAR 18:07Z
    FastMCP OAuth Proxy token reuse across MCP servers
    cvelistv5