MyComplianceOffice MCO 25.3.3.1 Group Membership group-membership privileges assignment

Summaryinfo

A vulnerability labeled as critical has been found in MyComplianceOffice MCO 25.3.3.1. This affects an unknown function of the file /customer/servlet/mco/webapi/profile-sections/group-membership of the component Group Membership Handler. The manipulation results in privileges assignment. This vulnerability is cataloged as CVE-2026-53902. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in MyComplianceOffice MCO 25.3.3.1. It has been classified as critical. Affected is an unknown part of the file /customer/servlet/mco/webapi/profile-sections/group-membership of the component Group Membership Handler. The manipulation with an unknown input leads to a privileges assignment vulnerability. CWE is classifying the issue as CWE-266. A product incorrectly assigns a privilege to a particular actor, creating an unintended sphere of control for that actor. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The weakness was shared with AFINE Team. The advisory is shared for download at cert.pl. This vulnerability is traded as CVE-2026-53902 since 06/11/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 07/01/2026). The MITRE ATT&CK project declares the attack technique as T1068.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

• MyComplianceOffice

Name

• MCO

Version

• 25.3.3.1

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CPE 2.2info

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