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.

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…

EPSS: 0.001 (27.3th percentile) — read the EPSS interpretation.

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.

Affected products

Userspice — versions 4.3.24

Weakness classification (CWE)

CWE-204 — Observable Response Discrepancy

References

disclosure@vulncheck.com (exploit)
disclosure@vulncheck.com (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.