CVE-2026-53905 Unauthorized Access to Administrator ACL View in MCO

Medium 5.3 Published 1 Jul 2026 Updated 1 Jul 2026

Low-privileged users can access administrator ACL structures in MCO due to missing authorization checks, exposing sensitive permission mappings.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-53905?

CVE-2026-53905 is a medium-severity missing authorization vulnerability in MyComplianceOffice MCO, published on 1 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

MCO does not properly enforce authorization checks in the /customer/servlet/mco/webapi/admin-view-hierarchy/get-acl-tree-structure endpoint. An authenticated, low-privileged user can retrieve administrator access control structures without proper authorization checks. This may expose sensitive permission mappings and internal configuration details.

Because vendor contact attempts were unsuccessful, the vulnerability has only been confirmed in version 25.3.3.1 but may also affect other versions.

Weakness: CWE-863

Which versions are affected by CVE-2026-53905?

It affects 1 product.

Products include Mycomplianceoffice Mycomplianceoffice.

How do I fix CVE-2026-53905?

No fix has been published for CVE-2026-53905 yet. Limit exposure of the affected software until one is available.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2026-53905 being exploited?

There is no known exploitation of CVE-2026-53905 in the wild and no public exploit code.

Sources

Also known as GHSA-4hjp-j24w-p3rr.