A critical authorization vulnerability in the Jenkins Microsoft Entra ID plugin allows authenticated users to escalate privileges by creating Entra groups with colliding display names.

The plugin incorrectly uses both unique object IDs and display names for group permission mapping. An attacker with low-level authenticated access can exploit this logic flaw to assume the permissions assigned to a privileged group by creating a new group with a matching display name.

Successful exploitation grants an attacker unauthorized administrative or elevated access within the Jenkins environment, leading to potential full system compromise. Given the CVSS score of 8.8, this flaw poses a high risk to organizational integrity, as it enables lateral movement and unauthorized manipulation of CI/CD pipelines.

Immediate Action: Review the official Jenkins security advisory at https://www.jenkins.io/security/advisory/2026-09-02/#SECURITY-3935 and apply the recommended plugin update as soon as it becomes available.

Proactive Monitoring: Monitor Jenkins access logs for unusual group membership changes or unauthorized attempts to create or modify Entra ID groups that align with existing privileged group names.

Compensating Controls: Restrict the ability to manage Entra ID groups to a minimal number of trusted administrators to prevent the creation of malicious group name collisions.

Public Exploit Available: Unknown

This vulnerability represents a significant risk to the security posture of CI/CD infrastructure. Administrators should prioritize updating the Microsoft Entra ID plugin immediately upon the release of a patched version to prevent potential privilege escalation and unauthorized access to build environments.