Vulnerability in Userspice
CVE-2018-25350
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.004 (35.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 35th percentile — 35.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
- Userspice — versions 4.3.24
Weakness classification (CWE)
References
- www.exploit-db.com/exploits/44872 (exploit)
- www.vulncheck.com/advisories/userspice-username-enumeration-via-existingusernam… (third-party-advisory)
Frequently asked questions
- What is CVE-2018-25350?
- CVE-2018-25350 is a critical-severity vulnerability in Userspice, classified under Observable Response Discrepancy. CVSS score: 9.8/10. Published 2026-05-23.
- How severe is CVE-2018-25350?
- Critical severity. CVSS v3 base score is 9.8 out of 10.