Vulnerability · Published Jul 1, 2026 · Assigned by CERT-PL
CVE-2026-53904Account Denial of Service in MCO
Medium 6.3
In plain English
A medium-severity security flaw in MCO from MyComplianceOffice. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 28% of all known vulnerabilities).
Official description
MCO is vulnerable to Account Denial of Service due to improper implementation of password reset functionality. Each password reset request invalidates previously set password as well as previously issued temporary passwords, furthermore, password resets are not limited in any way. An attacker who provides victim's email and answer to their security question, can successfully initiate the reset process and continuously invalidate credentials, effectively locking the victim out of their account. Answering security questions has a limited number of tries which lowers the risk of this vulnerability. Because vendor contact attempts were unsuccessful, the vulnerability has only been confirmed in version 25.3.3.1 but may also affect other versions.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| MyComplianceOffice | MCO | 25.3.3.1 |
Weakness: CWE-307, CWE-640 · Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
References
- https://cert.pl/en/posts/2026/07/CVE-2026-53902 third-party-advisory
- https://mco.mycomplianceoffice.com/ product