CVE-2026-53902: Mycomplianceoffice

Medium severity, CVSS 6.5. EPSS: 0.3% chance of exploitation in the next 30 days.

MCO does not properly enforce authorization checks in the /customer/servlet/mco/webapi/profile-sections/group-membership endpoint. An authenticated user can modify their group membership without proper authorization checks, allowing privilege escalation. An attacker can add themselves to arbitrary groups by supplying a valid group ID, which can be obtained via other application functionalities (e.g. /customer/servlet/mco/webapi/group/picker/groups), provided he has necessary permissions, or potentially inferred through brute-force techniques. Because vendor contact attempts were unsuccessful, the vulnerability has only been confirmed in version 25.3.3.1 but may also affect other versions.

Affected products

• Mycomplianceoffice Mycomplianceoffice: version 25.3.3.1 only

Published 2026-07-01. Last modified 2026-07-06.