Medium severity · published Mar 16, 2026
CVE-2025-69196
FastMCP OAuth Proxy token reuse across MCP servers
6.5
CVSS
0.4%
EPSS
No
On KEV
Description
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 31% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FA
fastmcp · jlowin
< 2.14.2 · source: vendor, NVD
RH
Red Hat Satellite 6.18 · Red Hat
All versions, or not specified · source: CISA
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-69196
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-69196
Exploit
https://github.com/PrefectHQ/fastmcp/security/advisories/GHSA-5h2m-4q8j-pqpj
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:36350
access.redhat.com
https://access.redhat.com/security/cve/CVE-2025-69196
bugzilla.redhat.com
https://bugzilla.redhat.com/show_bug.cgi?id=2448179
security.access.redhat.com
https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-69196.json
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