Vulnerability · Published Jul 1, 2026 · Assigned by CERT-PL
CVE-2026-53902Privilege Escalation in MCO
High 7.1
In plain English
A high-severity incorrect authorization in MCO from MyComplianceOffice. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 28% of all known vulnerabilities).
Official description
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 (as reported)
| Vendor | Product | Versions |
|---|---|---|
| MyComplianceOffice | MCO | 25.3.3.1 |
Weakness: CWE-266, CWE-863 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N
References
- https://cert.pl/en/posts/2026/07/CVE-2026-53902 third-party-advisory
- https://mco.mycomplianceoffice.com/ product