CVE-2026-53907 Stored Cross‑Site Scripting in MCO

Medium 4.8 Published 1 Jul 2026 Updated 1 Jul 2026

An attacker can execute arbitrary JavaScript in the MCO web application by uploading a malicious SVG logo, potentially compromising user sessions.

Exploited in the wild: Not known
Login needed: An administrator
Attackable: Over the internet
Victim action needed: A user has to click or open something
Fix: None listed

What is CVE-2026-53907?

CVE-2026-53907 is a medium-severity cross-site scripting vulnerability in MyComplianceOffice MCO, published on 1 Jul 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

Official description

MCO is vulnerable to Stored Cross‑Site Scripting (XSS) via the application logo upload functionality. An attacker with the ability to change the application logo can upload a crafted SVG file containing malicious JavaScript code that is executed when the logo is rendered or opened.

Because vendor contact attempts were unsuccessful, the vulnerability has only been confirmed in version 25.3.3.1 but may also affect other versions.

Weakness: CWE-79

Which versions are affected by CVE-2026-53907?

It affects 1 product.

Products include Mycomplianceoffice Mycomplianceoffice.

How do I fix CVE-2026-53907?

No fix has been published for CVE-2026-53907 yet. Limit exposure of the affected software until one is available.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2026-53907 being exploited?

There is no known exploitation of CVE-2026-53907 in the wild and no public exploit code.

Sources

Also known as GHSA-r38x-66p9-p239.