CVE-2025-31691: Drupal/oauth2 server Drupal OAuth2 Server Missing Authorization Vulnerability

HIGH
Advisory Identifier: GHSA-4f8q-mwgc-3mwc
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CVSS 9.8
CWE-862
Published
Advisory Summary

CVE-2025-31691 is a HIGH (CVSS 9.8) drupal oauth2 server missing authorization vulnerability (CWE-862: Missing Authorization) affecting Drupal/oauth2 server libraries in the Packagist ecosystem. The issue involves drupal oauth2 server missing authorization vulnerability. Remediation is available by upgrading affected packages to version 2.1.0.

CVE-2025-31691 at a Glance

CVE Identifier CVE-2025-31691
GHSA Identifier GHSA-4f8q-mwgc-3mwc
Severity HIGH
CVSS v3.1 Base Score 9.8
CWE Classification CWE-862: Missing Authorization
Affected Product Drupal/oauth2 server
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 9.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2025-31691

To remediate this vulnerability, upgrade all affected Drupal/oauth2 server dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

drupal/oauth2_server fixed: 2.1.0 
Upgrade drupal/oauth2_server to 2.1.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for drupal/oauth2_server

How to Check if You Are Affected

To determine whether your application is affected by CVE-2025-31691, inspect your project dependencies for Drupal/oauth2 server:

inspect dependencies for drupal/oauth2_server

Analyze the terminal output to locate any version of Drupal/oauth2 server in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.1.0), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-862: Missing Authorization, where the product does not perform an authorization check when an actor attempts to access a resource or perform an action. In Drupal/oauth2 server, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

Missing Authorization vulnerability in Drupal OAuth2 Server allows Forceful Browsing. This issue affects OAuth2 Server: from 0.0.0 before 2.1.0.

CVE-2025-31691 Affected Drupal/oauth2 server Versions

1 component(s)
Fixed Versions:
2.1.0
Product / Package Ecosystem Affected Versions Fixed Version
drupal/oauth2_server
 Packagist
< 2.1.0
2.1.0

References

NVD — CVE-2025-31691 NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-31691
git.drupalcode.org/project/oauth2_serv... PACKAGE
https://git.drupalcode.org/project/oauth2_server
www.drupal.org/sa-contrib-2025-020 WEB
https://www.drupal.org/sa-contrib-2025-020

Frequently Asked Questions

What is CVE-2025-31691?
CVE-2025-31691 is a security vulnerability in Drupal/oauth2 server involving Drupal OAuth2 Server Missing Authorization vulnerability under CWE-862: Missing Authorization.
Which Drupal/oauth2 server versions are affected?
Affected versions include releases prior to 2.1.0 across affected packages: drupal/oauth2_server.
What version fixes CVE-2025-31691?
Upgrading to 2.1.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is drupal/oauth2_server affected?
Yes, drupal/oauth2_server is affected in releases prior to 2.1.0. Upgrade your dependency to 2.1.0 or later.
What is the CVSS score of CVE-2025-31691?
CVE-2025-31691 has a CVSS v3.1 base score of 9.8 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2025-31691?
CVE-2025-31691 is classified under CWE-862: Missing Authorization (The product does not perform an authorization check when an actor attempts to access a resource or perform an action.).
How can I check Packagist dependencies for CVE-2025-31691?
Run the dependency tree command: 'inspect dependencies for drupal/oauth2_server'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-4f8q-mwgc-3mwc",
  "modified" : "2025-04-29T20:25:20Z",
  "published" : "2025-04-01T00:30:35Z",
  "aliases" : [ "CVE-2025-31691" ],
  "summary" : "Drupal OAuth2 Server Missing Authorization vulnerability",
  "details" : "Missing Authorization vulnerability in Drupal OAuth2 Server allows Forceful Browsing. This issue affects OAuth2 Server: from 0.0.0 before 2.1.0.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "drupal/oauth2_server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.1.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-31691"
  }, {
    "type" : "PACKAGE",
    "url" : "https://git.drupalcode.org/project/oauth2_server"
  }, {
    "type" : "WEB",
    "url" : "https://www.drupal.org/sa-contrib-2025-020"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-862" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-04-02T17:13:34Z",
    "nvd_published_at" : "2025-03-31T22:15:21Z"
  }
}