github - ghsa-qgp8-v765-qxx9

ghsa-qgp8-v765-qxx9

Vulnerability from github

Published

2025-05-01 17:01

Modified

2025-05-01 17:01

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

Summary

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

Details

Summary

PKCE was implemented in the OAuth implementation in workers-oauth-provider that is part of MCP framework. However, it was found that an attacker could cause the check to be skipped.

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.

Patches

Fixed in: https://github.com/cloudflare/workers-oauth-provider/pull/27

We patched up the vulnerabilities in the latest version, v 0.0.5 of the Workers OAuth provider (https://www.npmjs.com/package/@cloudflare/workers-oauth-provider). You'll need to update your MCP servers to use that version to resolve the vulnerability.

Workarounds

None

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "@cloudflare/workers-oauth-provider"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.0.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-4144"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-287"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-05-01T17:01:42Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Summary\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 was found that an attacker could cause the check to be skipped.\n\n### Impact\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.)\nThis bug completely bypasses PKCE protection.\n\n\n### Patches\nFixed in: https://github.com/cloudflare/workers-oauth-provider/pull/27\n\nWe patched up the vulnerabilities in the latest version, v 0.0.5 of the Workers OAuth provider (https://www.npmjs.com/package/@cloudflare/workers-oauth-provider). You\u0027ll need to update your MCP servers to use that version to resolve the vulnerability.\n\n### Workarounds\nNone",
  "id": "GHSA-qgp8-v765-qxx9",
  "modified": "2025-05-01T17:01:42Z",
  "published": "2025-05-01T17:01:42Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/cloudflare/workers-oauth-provider/security/advisories/GHSA-qgp8-v765-qxx9"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-4144"
    },
    {
      "type": "WEB",
      "url": "https://github.com/cloudflare/workers-oauth-provider/pull/27"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/cloudflare/workers-oauth-provider"
    }
  ],
  "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "@cloudflare/workers-oauth-provider PKCE bypass via downgrade attack"
}

cve-2025-4144

Vulnerability from cvelistv5

Published

2025-05-01 00:50

Modified

2025-05-01 15:33

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

Summary

PKCE bypass via downgrade attack

References

▼	URL	Tags
	https://github.com/cloudflare/workers-oauth-provider/pull/27

Impacted products

▼	Vendor	Product

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
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        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2025-4144",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-05-01T14:30:41.553527Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-05-01T15:33:23.092Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
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    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://github.com/cloudflare",
          "defaultStatus": "unaffected",
          "packageName": "workers-oauth-provider",
          "repo": "https://github.com/cloudflare/workers-oauth-provider",
          "versions": [
            {
              "lessThan": "0.0.5",
              "status": "affected",
              "version": "0",
              "versionType": "git"
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      ],
      "datePublic": "2025-04-30T16:30:00.000Z",
      "descriptions": [
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          "lang": "en",
          "supportingMedia": [
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              "value": "\u003cp\u003e\u003cspan style=\"background-color: transparent;\"\u003ePKCE was implemented in the OAuth implementation in workers-oauth-provider that is part of \u003c/span\u003e\u003ca target=\"_blank\" rel=\"nofollow\" href=\"https://github.com/cloudflare/workers-mcp\"\u003e\u003cspan style=\"background-color: transparent;\"\u003eMCP framework\u003c/span\u003e\u003c/a\u003e. However, it\u003cspan style=\"background-color: transparent;\"\u003e\u0026nbsp;was found that an attacker could cause the check to be skipped.\u003c/span\u003e\u003c/p\u003e\u003cb\u003e\u003cbr\u003e\u003c/b\u003e\u003cp\u003e\u003cspan style=\"background-color: transparent;\"\u003eFixed in:\u003c/span\u003e\u003c/p\u003e\u003cp\u003e \u003c/p\u003e\u003cp\u003e\u003ca target=\"_blank\" rel=\"nofollow\" href=\"https://github.com/cloudflare/workers-oauth-provider/pull/27\"\u003e\u003cspan style=\"background-color: transparent;\"\u003ehttps://github.com/cloudflare/workers-oauth-provider/pull/27\u003c/span\u003e\u003c/a\u003e\u003c/p\u003e\u003cb\u003e\u003cbr\u003e\u003c/b\u003e\u003cp\u003e\u003cspan style=\"background-color: transparent;\"\u003eImpact: \u003c/span\u003e\u003c/p\u003e\u003cp\u003e\u003cspan style=\"background-color: transparent;\"\u003ePKCE 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.).\u0026nbsp;\u003c/span\u003e\u003cspan style=\"background-color: transparent;\"\u003eThis bug completely bypasses PKCE protection.\u003c/span\u003e\u003c/p\u003e\u003cbr\u003e"
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      "metrics": [
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          "cvssV4_0": {
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            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM",
            "privilegesRequired": "NONE",
            "providerUrgency": "AMBER",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "PASSIVE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "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",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
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            "vulnerabilityResponseEffort": "NOT_DEFINED"
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          "scenarios": [
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      ],
      "providerMetadata": {
        "dateUpdated": "2025-05-01T00:50:27.543Z",
        "orgId": "a22f1246-ba21-4bb4-a601-ad51614c1513",
        "shortName": "cloudflare"
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      "references": [
        {
          "url": "https://github.com/cloudflare/workers-oauth-provider/pull/27"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "PKCE bypass via downgrade attack",
      "x_generator": {
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  "cveMetadata": {
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    "cveId": "CVE-2025-4144",
    "datePublished": "2025-05-01T00:50:27.543Z",
    "dateReserved": "2025-04-30T16:39:00.801Z",
    "dateUpdated": "2025-05-01T15:33:23.092Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1"
}

Action not permitted

ghsa-qgp8-v765-qxx9

Vulnerability from github

Summary

Impact

Patches

Workarounds

cve-2025-4144

Vulnerability from cvelistv5

Tags