Privilege Escalation in MCO
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Privilege escalation, Security bypass
- Confidentiality · integrity · availability
- Low · High · None
- Fix status
- No fix listed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-266 and CWE-863.
Summary
MCO does not properly enforce authorization checks in the /customer/servlet/mco/webapi/profile-sections/group-membership endpoint. An authenticated user can modify their group membership without proper authorization checks, allowing privilege escalation. An attacker can add themselves to arbitrary groups by supplying a valid group ID, which can be obtained via other application functionalities (e.g. /customer/servlet/mco/webapi/group/picker/groups), provided he has necessary permissions, or potentially inferred through brute-force techniques. 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
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-2026-53902
- 2026-10-03 Alias added: GHSA-rgv6-j8h9-46fv
References
More Mycomplianceoffice vulnerabilities
- TI-2026-38884 User Enumeration in MCO CVSS 4.0MEDIUM 6.9
- TI-2026-38885 Arbitrary File Upload in MCO CVSS 4.0MEDIUM 5.3
- 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-2026-53902 · CVE Program
- CVE-2026-53902 · NVD
- FIRST EPSS
- GHSA-rgv6-j8h9-46fv · GitHub Advisory Database · CC BY 4.0
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