CVE-2026-53909: Mycomplianceoffice

Medium severity, CVSS 6.5. EPSS: 0.4% chance of exploitation in the next 30 days.

MCO does not correctly validate types of uploaded files. File upload validation functionality relies only on client-side checks, which can be bypassed. An authorized, low-privileged attacker can upload files with arbitrary types to the server. 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.