CVE-2026-53909
Medium
Description
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.
SeverityMedium
CVSS6.5
Exploit probability34. percentile0.4%
ProductMycomplianceoffice
PublishedJul 1, 2026
First seenJul 1, 2026
Weakness typeCWE-434Unrestricted upload of dangerous file type
How to fix
Sources list no fixed version or patch link for this vulnerability.
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mycomplianceoffice mycomplianceoffice | 25.3.3.1 | — |
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