CVE-2026-53908: MCO is vulnerable to User Enumeration through authentication-related functionalities. The application returns distinguishable responses for valid and invalid users during username

mediumCVSS 4.3CVE-2026-53908

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.

Details

Source: NVD Recent CVEs (US · database · site)
Severity: medium — CVSS 4.3
Published: 2026-07-01
Last updated: 2026-07-06
Exploitation: Not in CISA KEV at last sync

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-53908

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-539080.21% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 11% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-53908	coverage & exploitation status	NVD · CVE.org

CVE-2026-53908: MCO is vulnerable to User Enumeration through authentication-related functionalities. The application returns distinguishable responses for valid and invalid users during username

Details

Exploitation outlook

Referenced CVEs

More from NVD Recent CVEs