Cyber Posture

CVE-2025-31691

Critical

Published: 31 March 2025

Published
31 March 2025
Modified
02 September 2025
KEV Added
Patch
CVSS Score 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0040 61.0th percentile
Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Description

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

Security Summary

CVE-2025-31691 is a missing authorization vulnerability (CWE-862) in the Drupal OAuth2 Server module that enables forceful browsing. The issue affects all versions of the OAuth2 Server module from 0.0.0 up to but not including 2.1.0.

Remote attackers require no privileges or user interaction to exploit this vulnerability over the network with low complexity, as indicated by its CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H). Unauthenticated attackers can leverage forceful browsing to bypass authorization controls, potentially achieving high impacts on confidentiality, integrity, and availability of the affected Drupal instance.

The Drupal security advisory SA-CONTRIB-2025-020, available at https://www.drupal.org/sa-contrib-2025-020, documents the vulnerability and provides guidance on mitigation, including upgrading to OAuth2 Server version 2.1.0 or later.

Details

CWE(s)
CWE-862

Affected Products

oauth2 server project
oauth2 server
≤ 2.1.0

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Why these techniques?

The CVE describes a critical unauthenticated remote authorization bypass (forceful browsing) in a public-facing Drupal OAuth2 Server module, directly enabling exploitation of public-facing applications for initial access with high impact on confidentiality, integrity, and availability.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

References