CVE-2003-0521
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 · uneditedCross-site scripting (XSS) vulnerability in cPanel 6.4.2 allows remote attackers to insert arbitrary HTML and possibly gain cPanel administrator privileges via script in a URL that is logged but not properly quoted when displayed via the (1) Error Log or (2) Latest Visitors screens.
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 confidenceStored XSS vulnerability in cPanel 6.4.2 allows remote attackers to inject arbitrary HTML/script via malicious URLs that get logged but are not properly sanitized when displayed in the Error Log or Latest Visitors screens. This could allow session hijacking and privilege escalation to cPanel administrator privileges.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data= 5.0= 5.3= 6.0= 6.2= 6.4= 6.4.1= 6.4.2= 6.4.2_stable_48CVSS 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
- M
- Authentication
- None
- Confidentiality
- Partial
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:M/Au:N/C:P/I:P/A:P
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 checksWork through these to decide whether this CVE applies to you.
-
Identify cPanel versionAccess WHM root shell or execute: grep -i version /var/cpanel/sysinfo.config or check /usr/local/cpanel/versionAffected if version matches 5.0, 5.3, 6.0, 6.2, 6.4, 6.4.1, 6.4.2, or 6.4.2_stable_48
-
Check if Error Log interface is accessibleLog into cPanel as any user and navigate to Errors section in the cPanel interface, or inspect /usr/local/cpanel/logs/error_log directlyAffected if Error Log is viewable and displays raw logged URLs without HTML encoding
-
Check if Latest Visitors interface is accessibleLog into cPanel as any user and access the Latest Visitors (Analog Stats) feature in the Logs sectionAffected if Latest Visitors page renders logged URLs without sanitization
-
Inspect logs for injected script contentSearch cPanel error logs for patterns like '<script>', 'javascript:', or HTML tags in what should be URL fields: grep -i '<script>' /usr/local/cpanel/logs/error_logAffected if Log entries contain unescaped HTML or JavaScript code in URL fields
If cPanel version falls within the affected range and the Error Log or Latest Visitors screens display logged URLs with raw HTML/script tags, the system is vulnerable to CVE-2003-0521.
Generated from the published advisory. Verify against your own configuration.
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 dataUpgrade cPanel to a patched version that addresses this vulnerability. If immediate upgrade is not feasible, restrict administrative access to the Error Log and Latest Visitors interfaces until the system can be patched.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2003-0521 — 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 sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2003-0521 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
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.
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.
- 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