FastMCP OAuth Proxy token reuse across MCP servers

Summary

CVECVE-2025-69196
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-03-16 19:16:14 UTC
Updated2026-06-30 03:16:58 UTC
DescriptionFastMCP 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.

Risk And Classification

Primary CVSS: v4.0 7.4 HIGH from [email protected]

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS: 0.003580000 probability, percentile 0.277970000 (date 2026-07-02)

Problem Types: CWE-863 | CWE-1220 | CWE-863 CWE-863: Incorrect Authorization | CWE-1220 Insufficient Granularity of Access Control


VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary7.4HIGHCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/C...
4.0CNADECLARED7.4HIGHCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
3.1[email protected]Primary6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
3.1ADPCVSS7.4HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
3.10b0ca135-0b70-47e7-9f44-1890c2a1c46cSecondary7.4HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
High
Attack Requirements
None
Privileges Required
None
User Interaction
Active
Confidentiality
High
Integrity
High
Availability
None
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Jlowin Fastmcp All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Jlowin Fastmcp affected < 2.14.2 Not specified
ADP Red Hat Red Hat Satellite 6 Not specified Not specified
ADP Red Hat Red Hat Developer Hub Not specified Not specified
ADP Red Hat Red Hat OpenShift AI RHOAI Not specified Not specified

References

ReferenceSourceLinkTags
security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-69196.json 0b0ca135-0b70-47e7-9f44-1890c2a1c46c security.access.redhat.com
bugzilla.redhat.com/show_bug.cgi 0b0ca135-0b70-47e7-9f44-1890c2a1c46c bugzilla.redhat.com
access.redhat.com/security/cve/CVE-2025-69196 0b0ca135-0b70-47e7-9f44-1890c2a1c46c access.redhat.com
github.com/PrefectHQ/fastmcp/security/advisories/GHSA-5h2m-4q8j-pqpj [email protected] github.com Exploit, Mitigation, Vendor Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Additional Advisory Data

SourceTimeEvent
ADP2026-03-16T19:01:37.622ZReported to Red Hat.
ADP2026-03-16T18:07:06.332ZMade public.
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