Vulnerability in Mycomplianceoffice Mco
CVE-2026-53908
MCO is vulnerable to User Enumeration through authentication-related functionalities. The application returns distinguishable responses for valid and invalid users during username reminder and password reset operations. An attacker can leverage these differences to enumerate valid usernames and email addresses. Because vendor contact attempts were unsuccessful, the vulnerability has only been confirmed in version 25.3.3.1 but may also affect other versions.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.
EPSS exploit prediction
EPSS: 0.004 (27.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 28th percentile — 27.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
- Mycomplianceoffice Mco — versions 25.3.3.1
- Mycomplianceoffice — versions 25.3.3.1
Weakness classification (CWE)
References
- cert.pl/en/posts/2026/07/CVE-2026-53902 (Third Party Advisory, third-party-advisory)
- mco.mycomplianceoffice.com/ (Product, product)
Frequently asked questions
- What is CVE-2026-53908?
- CVE-2026-53908 is a medium-severity vulnerability in Mycomplianceoffice Mco, classified under Observable Response Discrepancy. CVSS score: 4.3/10. Published 2026-07-01.
- How severe is CVE-2026-53908?
- Medium severity. CVSS v3 base score is 4.3 out of 10.