CWE-204Weakness · CWE-204

CVE-2018-25350

CRITICAL · 9.8 CVSS v3.1 Published 2026-05-23
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Public exploit Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

userSpice 4.3.24 has a username enumeration vulnerability in the existingUsernameCheck.php endpoint. Unauthenticated attackers can submit POST requests with usernames and analyze responses for the 'taken' string to identify valid user accounts in the system.

MitigationRestrict access to the existingUsernameCheck.php endpoint by requiring authentication, implementing rate limiting, or modifying the response to return identical messages regardless of username validity to prevent enumeration.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify userSpice installation
    Search the web root for userSpice files such as 'userspice', 'us_manage.php', or directories containing 'userSpice' branding
    Affected if userSpice framework is present on the system
  2. Determine userSpice version
    Locate a version file (e.g., version.php) in the userSpice root directory or check the footer/included files for version strings like '4.3'
    Affected if Installed version is 4.3.24 or falls within the 4.x branch prior to patching
  3. Verify vulnerable endpoint exists
    Check for the existence of 'existingUsernameCheck.php' in the web-accessible directory, typically under the users/ or root path
    Affected if The file existingUsernameCheck.php exists on the server
  4. Test unauthenticated access to enumeration endpoint
    Send a POST request to existingUsernameCheck.php with a parameter like 'username=anyname' without providing any authentication cookies or headers, then inspect the response body
    Affected if The endpoint returns a response without requiring authentication and the response contains either 'taken' or 'available' based on username existence

A user is affected if userSpice 4.3.24 is installed and the existingUsernameCheck.php endpoint is accessible without authentication, allowing attackers to enumerate valid usernames via the 'taken' response string.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Restrict access to the existingUsernameCheck.php endpoint by requiring authentication, implementing rate limiting, or modifying the response to return identical messages regardless of username validity to prevent enumeration.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2018-25350 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-25350 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data