GHSA-VH4H-FVQF-Q9WV

Vulnerability from github – Published: 2025-05-01 03:31 – Updated: 2025-05-01 17:01

Summary

Duplicate Advisory: @cloudflare/workers-oauth-provider PKCE bypass via downgrade attack

Details

Duplicate Advisory

This advisory has been withdrawn because it is a duplicate of GHSA-qgp8-v765-qxx9. This link is maintained to preserve external references.

Original Description

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.

Severity ?

5.3 (Medium)


                  
                    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

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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "@cloudflare/workers-oauth-provider"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.0.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-287"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-05-01T17:01:33Z",
    "nvd_published_at": "2025-05-01T01:15:54Z",
    "severity": "MODERATE"
  },
  "details": "# Duplicate Advisory\nThis advisory has been withdrawn because it is a duplicate of GHSA-qgp8-v765-qxx9. This link is maintained to preserve external references.\n\n# Original Description\nPKCE 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.",
  "id": "GHSA-vh4h-fvqf-q9wv",
  "modified": "2025-05-01T17:01:34Z",
  "published": "2025-05-01T03:31:17Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-4144"
    },
    {
      "type": "WEB",
      "url": "https://github.com/cloudflare/workers-oauth-provider/pull/27"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "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/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:Amber",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Duplicate Advisory: @cloudflare/workers-oauth-provider PKCE bypass via downgrade attack",
  "withdrawn": "2025-05-01T17:01:33Z"
}

CVE-2025-4144 (GCVE-0-2025-4144)

Vulnerability from cvelistv5 – Published: 2025-05-01 00:50 – Updated: 2025-05-01 15:33

Summary

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.

Severity ?

5.3 (Medium)


                        
                          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

CWE

CWE-287 - Improper Authentication

Assigner

cloudflare

References

URL

Tags

https://github.com/cloudflare/workers-oauth-provi…

Impacted products

	Vendor	Product	Version
			Affected: 0 , < 0.0.5 (git)

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                "id": "CVE-2025-4144",
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                "timestamp": "2025-05-01T14:30:41.553527Z",
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Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

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