Arbitrary File Upload in MCO
Priority LOW 24CWE-434Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Code execution
- Confidentiality · integrity · availability
- None · None · None
- Fix status
- No fix listed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-434.
Summary
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.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00394 33rd percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| MyComplianceOffice | MCO | 25.3.3.1 | — | No fix listed | CNA |
- MCO VendorMyComplianceOffice Affected 25.3.3.1 Fixed in — No fix listed CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:mycomplianceoffice:mycomplianceoffice:25.3.3.1:*:*:*:*:*:*:* | 25.3.3.1 | Vulnerable | MyComplianceOffice |
- cpe:2.3:a:mycomplianceoffice:mycomplianceoffice:25.3.3.1:*:*:*:*:*:*:* Versions 25.3.3.1 Vulnerable ·MyComplianceOffice
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-53909
- 2026-10-03 Alias added: GHSA-5v97-p7p8-r448
References
More Mycomplianceoffice vulnerabilities
- TI-2026-38884 User Enumeration in MCO CVSS 4.0MEDIUM 6.9
- TI-2026-38878 Privilege Escalation in MCO CVSS 4.0HIGH 7.1
- TI-2026-38882 Path Disclosure and Path Traversal in MCO CVSS 4.0MEDIUM 5.1
- TI-2026-38881 Unauthorized Access to Administrator ACL View in MCO CVSS 4.0MEDIUM 5.3
- TI-2026-38879 Insecure Direct Object Reference in MCO CVSS 4.0MEDIUM 5.3
- TI-2026-38883 Stored Cross‑Site Scripting in MCO CVSS 4.0MEDIUM 4.8
Sources
- CVE-2026-53909 · CVE Program
- CVE-2026-53909 · NVD
- FIRST EPSS
- GHSA-5v97-p7p8-r448 · GitHub Advisory Database · CC BY 4.0
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