CVE-2018-25350: Userspice

Critical severity, CVSS 9.8. EPSS: 0.4% chance of exploitation in the next 30 days.

userSpice 4.3.24 contains a username enumeration vulnerability that allows unauthenticated attackers to discover valid usernames by sending POST requests to the existingUsernameCheck.php endpoint. Attackers can submit usernames and analyze response text for the 'taken' string to identify existing accounts in the system.

Affected products

• Userspice Userspice: version 4.3.24 only

Published 2026-05-23. Last modified 2026-10-06.