{"uuid": "21f4bbe2-c622-4ecb-8983-c86d21ce1881", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "2a075640-a300-48a4-bb44-bc6130783b9b", "vulnerability": "CVE-2025-4144", "type": "published-proof-of-concept", "source": "https://t.me/DarkWebInformer_CVEAlerts/14209", "content": "\ud83d\udd17 DarkWebInformer.com - Cyber Threat Intelligence\n\ud83d\udccc CVE ID: CVE-2025-4144\n\ud83d\udd25 CVSS Score: 5.3 (cvssV4_0, 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)\n\ud83d\udd39 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\u00a0was found that an attacker could cause the check to be skipped.\n\n\nFixed in:\n\n \n\n https://github.com/cloudflare/workers-oauth-provider/pull/27 https://github.com/cloudflare/workers-oauth-provider/pull/27 \n\n\nImpact: \n\nPKCE 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.).\u00a0This bug completely bypasses PKCE protection.\n\ud83d\udccf Published: 2025-05-01T00:50:27.543Z\n\ud83d\udccf Modified: 2025-05-01T00:50:27.543Z\n\ud83d\udd17 References:\n1. https://github.com/cloudflare/workers-oauth-provider/pull/27", "creation_timestamp": "2025-05-01T01:13:32.000000Z"}