CVE-2026-53908CWE-204

User Enumeration in MCO

Medium · published July 1, 2026

CVSS v4.0
6.9
EPSS
0%
Percentile
28.7
In the wild
Unconfirmed
What it is

MCO is vulnerable to User Enumeration through authentication-related functionalities. The application returns distinguishable responses for valid and invalid users during username reminder and password reset operations. An attacker can leverage these differences to enumerate valid usernames and email addresses.

Because vendor contact attempts were unsuccessful, the vulnerability has only been confirmed in version 25.3.3.1 but may also affect other versions.

The record
Technical detail
CVSS v4.0
6.9 · MEDIUM
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
EPSS
0.00361 · 28.7th percentile
Weakness
CWE-204 · Observable Response Discrepancy
Published
2026-07-01T11:59Z
EPSS history
Timeline
  • 01 JUL 11:59Z
    User Enumeration in MCO
    cvelistv5