What is CVE-2026-53907?

CVE-2026-53907 is a medium-severity vulnerability in Mycomplianceoffice Mco, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2026-07-01.

How severe is CVE-2026-53907?

Medium severity. CVSS v3 base score is 5.4 out of 10.

XSS in Mycomplianceoffice Mco

CVE-2026-53907

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.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.001 (3.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

Affected products

Mycomplianceoffice Mco — versions 25.3.3.1
Mycomplianceoffice — versions 25.3.3.1

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

cvd@cert.pl (Third Party Advisory, third-party-advisory)
cvd@cert.pl (Product, product)

Frequently asked questions

What is CVE-2026-53907?: CVE-2026-53907 is a medium-severity vulnerability in Mycomplianceoffice Mco, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2026-07-01.
How severe is CVE-2026-53907?: Medium severity. CVSS v3 base score is 5.4 out of 10.