Laravel Passport's TokenGuard Authenticates Unrelated User for Client Credentials Tokens

{
  "id": "aa3249b2d0097e1f99c502612fc87f920d483b1bd666e20ffdc77575c01b500a",
  "url": "https://osv.dev/vulnerability/CVE-2026-39976",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Laravel Passport's TokenGuard Authenticates Unrelated User for Client Credentials Tokens",
    "summary": "Laravel Passport provides OAuth2 server support to Laravel. From 13.0.0 to before 13.7.1, there is an Authentication Bypass for client_credentials tokens. the league/oauth2-server library sets the JWT sub claim to the client identifier (since there's no user). The token guard then passes this value to retrieveById() without validating it's actually a user identifier, potentially resolving an unrelated real user. Any machine-to-machine token can inadvertently authenticate as an actual user. This vulnerability is fixed in 13.7.1.",
    "evidence": "osv:CVE-2026-39976",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-39976",
      "aliases": [
        "CVE-2026-39976",
        "GHSA-349c-2h2f-mxf6"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/laravel/passport",
              "type": "GIT",
              "events": [
                {
                  "introduced": "1d89db335f9b6628f5ebeca8b64e3f7cbd89ec8b"
                },
                {
                  "fixed": "ca14d978801d328dc5b425af37781db9fcbace8c"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "13.0.0"
                      },
                      {
                        "fixed": "13.7.1"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "cpe": "cpe:2.3:a:laravel:passport:*:*:*:*:*:laravel:*:*",
                    "range": [
                      {
                        "introduced": "13.0.0"
                      },
                      {
                        "fixed": "13.7.1"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v13.7.0",
            "v13.6.0",
            "v13.5.0",
            "v13.4.4",
            "v13.4.3",
            "v13.4.2",
            "v13.4.1",
            "v13.4.0",
            "v13.3.0",
            "v13.2.2",
            "v13.2.1",
            "v13.2.0",
            "v13.1.0",
            "v13.0.6",
            "v13.0.5",
            "v13.0.4",
            "v13.0.3",
            "v13.0.2",
            "v13.0.1",
            "v13.0.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-39976.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:22.434396703Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39976.json",
        "https://github.com/laravel/passport/security/advisories/GHSA-349c-2h2f-mxf6",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-39976",
        "https://github.com/laravel/passport/issues/1900",
        "https://github.com/thephpleague/oauth2-server/issues/1456#issuecomment-2734989996",
        "https://github.com/laravel/passport/pull/1901",
        "https://github.com/laravel/passport/pull/1902"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-287"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39976.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-39976",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 488677,
  "published_at": "2026-04-09T16:50:42.326+00:00"
}