CVE-2025-31691
OAuth2 Server - Moderately critical - Access bypass - SA-CONTRIB-2025-020
Missing Authorization vulnerability in Drupal OAuth2 Server allows Forceful Browsing.This issue affects OAuth2 Server: from 0.0.0 before 2.1.0.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
OAuth2 Server - Moderately critical - Access bypass - SA-CONTRIB-2025-020
Missing Authorization vulnerability in Drupal OAuth2 Server allows Forceful Browsing.This issue affects OAuth2 Server: from 0.0.0 before 2.1.0.
- Record
CVE-2025-31691- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-862
- Updated
- 2026-11-02
EUVDEUVD-2025-9026
Missing Authorization vulnerability in Drupal OAuth2 Server allows Forceful Browsing.This issue affects OAuth2 Server: from 0.0.0 before 2.1.0.
- Record
EUVD-2025-9026- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-4f8q-mwgc-3mwc
Drupal OAuth2 Server Missing Authorization vulnerability
Missing Authorization vulnerability in Drupal OAuth2 Server allows Forceful Browsing. This issue affects OAuth2 Server: from 0.0.0 before 2.1.0.
- Record
GHSA-4f8q-mwgc-3mwc- CVSS 4.0
- 8.1 High
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 - CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-862
- Updated
- 2026-11-02
NVD
Missing Authorization vulnerability in Drupal OAuth2 Server allows Forceful Browsing.This issue affects OAuth2 Server: from 0.0.0 before 2.1.0.
- Record
CVE-2025-31691- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-862
- Updated
- 2026-11-02
OSV
OAuth2 Server - Moderately critical - Access bypass - SA-CONTRIB-2025-020
Missing Authorization vulnerability in Drupal OAuth2 Server allows Forceful Browsing.This issue affects OAuth2 Server: from 0.0.0 before 2.1.0.
- Record
CVE-2025-31691- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-862
- Updated
- 2026-11-02
OSVGHSA-4f8q-mwgc-3mwc
Drupal OAuth2 Server Missing Authorization vulnerability
Missing Authorization vulnerability in Drupal OAuth2 Server allows Forceful Browsing. This issue affects OAuth2 Server: from 0.0.0 before 2.1.0.
- Record
GHSA-4f8q-mwgc-3mwc- CVSS 4.0
- 8.1 High
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 - CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-862
- Updated
- 2026-11-02
OSVDRUPAL-CONTRIB-2025-020No score
Provides OAuth2 server functionality based on the oauth2-server-php library.
The module does not consistently enforce admin configurations allowing users on a disabled server to still authenticate.
- Record
DRUPAL-CONTRIB-2025-020- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
drupal/oauth2_serverPackagist | before 2.1.0 | 2.1.0 |
drupal/oauth2_serverPackagist:https://packages.drupal.org/8 | before 2.1.0 | 2.1.0 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-31691 is a critical vulnerability (CVSS 9.8) in Drupal Oauth2 Server, published February 26, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.43%, the 38th percentile. Fixed in drupal/oauth2_server 2.1.0.