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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2025-4144 Detail

Description

PKCE was implemented in the OAuth implementation in workers-oauth-provider that is part of MCP framework https://github.com/cloudflare/workers-mcp . However, it was found that an attacker could cause the check to be skipped. Fixed in: https://github.com/cloudflare/workers-oauth-provider/pull/27 https://github.com/cloudflare/workers-oauth-provider/pull/27 Impact: PKCE is a defense-in-depth mechanism against certain kinds of attacks and was an optional extension in OAuth 2.0 which became required in the OAuth 2.1 draft. (Note that the MCP specification requires OAuth 2.1.). This bug completely bypasses PKCE protection.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

Nist CVSS score does not match with CNA score
CNA:  Cloudflare, Inc.
CVSS-B 5.3 MEDIUM
Vector:  CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/U:Amber

References to Advisories, Solutions, and Tools

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Hyperlink Resource
https://github.com/cloudflare/workers-oauth-provider/pull/27 Issue Tracking  Patch 

Weakness Enumeration

CWE-ID CWE Name Source
NVD-CWE-noinfo Insufficient Information cwe source acceptance level NIST  
CWE-287 Improper Authentication Cloudflare, Inc.  

Known Affected Software Configurations Switch to CPE 2.2

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Change History

2 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2025-4144
NVD Published Date:
04/30/2025
NVD Last Modified:
05/12/2025
Source:
Cloudflare, Inc.