CVE-2026-53909MCO does not correctly validate types of uploaded files.
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 6.5 MEDIUM (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
- Weakness (CWE)
- CWE-434
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Not given
- NVD analysis
- Analyzed
- Record last updated
- Jul 6, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
mycomplianceoffice mycomplianceoffice mycomplianceoffice:mycomplianceoffice | 25.3.3.1 | NVD |
References
- https://cert.pl/en/posts/2026/07/CVE-2026-53902third-party-advisory
- https://mco.mycomplianceoffice.com/product
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.