Vulnerability-Lookup

GHSA-349C-2H2F-MXF6

Vulnerability from github – Published: 2026-04-08 19:57 – Updated: 2026-04-13 17:48

Summary

Laravel Passport: TokenGuard Authenticates Unrelated User for Client Credentials Tokens

Details

Impact

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.

Usage of EnsureClientIsResourceOwner middleware together with Passport::$clientUuids set to false, can result in resolving the user instead, as stated in the documentation.

The underlying OAuth2 server sets the token's sub claim to the client's identifier for client credentials tokens. By default, Passport uses UUIDs for clients, so this cannot collide with a user's integer primary key. However, if you have set Passport::$clientUuids to false, a client credentials token may inadvertently resolve a user whose ID matches the client's ID. In such cases, using this middleware cannot guarantee that the incoming token is a client credentials token.

Patches

Patched in v13.7.1

Workarounds

Is there a way for users to fix or remediate the vulnerability without upgrading? Disallow usage of client_credentials.

References

https://github.com/laravel/passport/issues/1900
https://github.com/laravel/passport/pull/1901
https://github.com/laravel/passport/pull/1902
https://github.com/thephpleague/oauth2-server/issues/1456#issuecomment-2734989996

Severity ?

7.1 (High)


                  
                    CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "laravel/passport"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "13.0.0"
            },
            {
              "fixed": "13.7.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-39976"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-287"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-08T19:57:55Z",
    "nvd_published_at": "2026-04-09T17:16:31Z",
    "severity": "HIGH"
  },
  "details": "### Impact\nAuthentication Bypass for `client_credentials` tokens. the league/oauth2-server library sets the JWT sub claim to the client identifier (since there\u0027s no user). The token guard then passes this value to retrieveById() without validating it\u0027s actually a user identifier, potentially resolving an unrelated real user. Any machine-to-machine token can inadvertently authenticate as an actual user.\n\n\nUsage of `EnsureClientIsResourceOwner` middleware together with `Passport::$clientUuids` set to `false`, can result in resolving the user instead, as stated in the [documentation](https://laravel.com/docs/13.x/passport#:~:text=The%20underlying%20OAuth2,client%20credentials%20token). \n\n\u003e The [underlying OAuth2 server](https://oauth2.thephpleague.com/database-setup/#:~:text=Please%20note%20that,the%20bearer%20token.) sets the token\u0027s sub claim to the client\u0027s identifier for client credentials tokens. By default, Passport uses UUIDs for clients, so this cannot collide with a user\u0027s integer primary key. However, if you have set Passport::$clientUuids to false, a client credentials token may inadvertently resolve a user whose ID matches the client\u0027s ID. In such cases, using this middleware cannot guarantee that the incoming token is a client credentials token.\n\n### Patches\nPatched in v13.7.1\n\n### Workarounds\n_Is there a way for users to fix or remediate the vulnerability without upgrading?_\nDisallow usage of `client_credentials`. \n\n\n### References\n- https://github.com/laravel/passport/issues/1900\n- https://github.com/laravel/passport/pull/1901\n- https://github.com/laravel/passport/pull/1902\n- https://github.com/thephpleague/oauth2-server/issues/1456#issuecomment-2734989996",
  "id": "GHSA-349c-2h2f-mxf6",
  "modified": "2026-04-13T17:48:46Z",
  "published": "2026-04-08T19:57:55Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/laravel/passport/security/advisories/GHSA-349c-2h2f-mxf6"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-39976"
    },
    {
      "type": "WEB",
      "url": "https://github.com/laravel/passport/issues/1900"
    },
    {
      "type": "WEB",
      "url": "https://github.com/thephpleague/oauth2-server/issues/1456#issuecomment-2734989996"
    },
    {
      "type": "WEB",
      "url": "https://github.com/laravel/passport/pull/1901"
    },
    {
      "type": "WEB",
      "url": "https://github.com/laravel/passport/pull/1902"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/laravel/passport"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Laravel Passport: TokenGuard Authenticates Unrelated User for Client Credentials Tokens"
}

CVE-2026-39976 (GCVE-0-2026-39976)

Vulnerability from cvelistv5 – Published: 2026-04-09 16:50 – Updated: 2026-04-09 19:31

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.

Severity ?

7.1 (High)


                        
                          CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N

CWE

CWE-287 - Improper Authentication

Assigner

GitHub_M

References

URL

Tags

	https://github.com/laravel/passport/security/advi…	x_refsource_CONFIRM
	https://github.com/laravel/passport/issues/1900	x_refsource_MISC
	https://github.com/thephpleague/oauth2-server/iss…	x_refsource_MISC
	https://github.com/laravel/passport/pull/1901	x_refsource_MISC
	https://github.com/laravel/passport/pull/1902	x_refsource_MISC

Impacted products

	Vendor	Product	Version
	laravel	passport	Affected: >= 13.0.0, < 13.7.1

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-39976",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-09T17:38:00.854614Z",
                "version": "2.0.3"
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              "type": "ssvc"
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        "providerMetadata": {
          "dateUpdated": "2026-04-09T19:31:53.801Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
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    "cna": {
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          "vendor": "laravel",
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        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 7.1,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N",
            "version": "3.1"
          }
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      ],
      "problemTypes": [
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          "descriptions": [
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              "cweId": "CWE-287",
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              "lang": "en",
              "type": "CWE"
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      "providerMetadata": {
        "dateUpdated": "2026-04-09T16:50:42.326Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
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      },
      "references": [
        {
          "name": "https://github.com/laravel/passport/security/advisories/GHSA-349c-2h2f-mxf6",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/laravel/passport/security/advisories/GHSA-349c-2h2f-mxf6"
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          "name": "https://github.com/laravel/passport/issues/1900",
          "tags": [
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          "url": "https://github.com/laravel/passport/issues/1900"
        },
        {
          "name": "https://github.com/thephpleague/oauth2-server/issues/1456#issuecomment-2734989996",
          "tags": [
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        },
        {
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          "tags": [
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        {
          "name": "https://github.com/laravel/passport/pull/1902",
          "tags": [
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          "url": "https://github.com/laravel/passport/pull/1902"
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      "source": {
        "advisory": "GHSA-349c-2h2f-mxf6",
        "discovery": "UNKNOWN"
      },
      "title": "Laravel Passport\u0027s TokenGuard Authenticates Unrelated User for Client Credentials Tokens"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
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    "datePublished": "2026-04-09T16:50:42.326Z",
    "dateReserved": "2026-04-08T00:01:47.628Z",
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    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Action not permitted

GHSA-349C-2H2F-MXF6

Impact

Patches

Workarounds

References

CVE-2026-39976 (GCVE-0-2026-39976)

Tags

Sightings

Nomenclature