CVE-2026-53909

UNKNOWN 0.0

Arbitrary File Upload in MCO

CVSS Score

0.0

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-434
Vendor	mycomplianceoffice
Product	mco
Published	Jul 1, 2026
Last Updated	Jul 1, 2026

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Affected Versions

MyComplianceOffice / MCO

25.3.3.1

References

NVD ↗ CVE.org ↗ EPSS Data ↗

cert.pl: https://cert.pl/en/posts/2026/07/CVE-2026-53902 mco.mycomplianceoffice.com: https://mco.mycomplianceoffice.com/

Credits

Hubert Decyusz (AFINE Team)