CVE-2026-11914: Drupal Composer Security Vulnerability

CVE-2026-11914 Overview

CVE-2026-11914 is an improper input validation vulnerability [CWE-20] affecting the Drupal Composer contributed module. The flaw allows an authenticated attacker with high privileges to compromise confidentiality and integrity through a network-based attack path. Successful exploitation requires elevated privileges and high attack complexity, limiting the pool of viable adversaries.

The Drupal Security Team published an advisory tracking this issue as SA-CONTRIB-2026-046. The vulnerability affects Composer versions as published in the advisory. No public exploit is currently available, and the issue is not listed on the CISA Known Exploited Vulnerabilities catalog.

Critical Impact
Authenticated attackers with high privileges can compromise the confidentiality and integrity of Drupal sites running affected Composer module versions.

Affected Products

Drupal Composer contributed module (versions specified in SA-CONTRIB-2026-046)
Drupal sites using the Composer module for dependency management
Any downstream Drupal distribution bundling the affected module

Discovery Timeline

2026-07-10 - CVE-2026-11914 published to NVD
2026-07-13 - Last updated in NVD database

Technical Details for CVE-2026-11914

Vulnerability Analysis

CVE-2026-11914 originates in the Drupal Composer contributed module. The root weakness is improper input validation [CWE-20]. The module accepts input that is not sufficiently sanitized or validated before use, enabling an attacker to influence subsequent processing logic.

Because the attack vector is network-based, an adversary can reach the vulnerable code path over standard HTTP or HTTPS to the Drupal application. However, exploitation requires authentication with high privileges, meaning the attacker must already control a privileged account or coerce one into acting. High attack complexity indicates additional conditions must align for the exploit to succeed.

Impact is scoped to confidentiality and integrity, with no direct availability impact. An attacker who succeeds can read data they should not access and modify state within the application's trust boundary.

Root Cause

The root cause is classified under [CWE-20] Improper Input Validation. The Composer module fails to correctly validate or constrain input before it flows into downstream logic. See the Drupal Security Advisory for module-specific technical details.

Attack Vector

Exploitation requires network reachability to the Drupal application and an authenticated session holding high privileges. The attacker submits crafted input that bypasses validation checks, triggering the vulnerable code path. No user interaction is required to complete the attack once the malicious request is sent.

No verified proof-of-concept code has been published for CVE-2026-11914. Refer to the vendor advisory for authoritative technical detail on the vulnerable input handling.

Detection Methods for CVE-2026-11914

Indicators of Compromise

Unexpected changes to Composer module configuration or dependency manifests within the Drupal site
Anomalous requests from privileged accounts targeting Composer module endpoints
Unauthorized modifications to files or database records writable by high-privilege Drupal roles

Detection Strategies

Audit Drupal watchdog and access logs for requests to Composer module routes originating from administrative sessions
Correlate privileged user session activity with configuration or content changes that fall outside normal workflows
Baseline expected Composer module usage and alert on deviations in request payloads and parameter values

Monitoring Recommendations

Forward Drupal application logs and web server access logs to a central analytics platform for long-term retention
Monitor for the creation or modification of administrator accounts that could satisfy the high-privilege precondition
Track integrity of Drupal codebase and Composer-managed dependencies using file integrity monitoring

How to Mitigate CVE-2026-11914

Immediate Actions Required

Review the Drupal Security Advisory SA-CONTRIB-2026-046 and identify affected Composer module versions in your environment
Update the Composer contributed module to the fixed version listed in the advisory
Audit privileged Drupal accounts and revoke unused or dormant high-privilege access

Patch Information

Apply the fixed release of the Drupal Composer contributed module as specified in the Drupal Security Advisory. Verify the installed version after update using standard Drupal module management tooling.

Workarounds

Restrict access to Composer module functionality to a minimal set of administrators until patching is complete
Enforce multi-factor authentication on all Drupal accounts holding high-privilege roles to reduce credential-based compromise
Place the Drupal administrative interface behind network access controls such as VPN or IP allow-listing where feasible

bash

# Configuration example: update Drupal Composer module via Composer
composer update drupal/composer --with-dependencies
drush cache:rebuild
drush pm:list --type=module --status=enabled | grep composer