Path Traversal in Mycomplianceoffice Mco
CVE-2026-53906
MCO is vulnerable to Path Disclosure and Path Traversal in file handling functionality related to data export and upload. Improper validation of the filename parameter allows writing files to arbitrary locations as well as indirect disclosure of absolute server paths through error messages. 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: Path Traversal (Directory Traversal)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N.
EPSS exploit prediction
EPSS: 0.005 (42.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 42nd percentile — 42.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · 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-2026-53906?
- CVE-2026-53906 is a high-severity vulnerability in Mycomplianceoffice Mco, classified under Path Traversal. CVSS score: 8.2/10. Published 2026-07-01.
- How severe is CVE-2026-53906?
- High severity. CVSS v3 base score is 8.2 out of 10.