CVE-2003-0283
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 Phorum before 3.4.3 allows remote attackers to inject arbitrary web script and HTML tags via a message with a "<<" before a tag name in the (1) subject, (2) author's name, or (3) author's e-mail.
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 confidenceCross-site scripting (XSS) vulnerability in Phorum before version 3.4.3 allows remote attackers to inject arbitrary web script and HTML tags through the subject line, author name, or author email fields by using a '<<' pattern before a tag name, bypassing input sanitization.
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<= 3.4.3CVSS 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.
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Identify if Phorum is installedCheck your web server for Phorum installation directories or search for Phorum-related files (commonly in /phorum, /forum, or similar paths). Look for index.php or common.php files that indicate a Phorum installation.Affected if Phorum software is present on the server
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Determine the installed Phorum versionLocate the version information file in the Phorum installation. Common locations include a VERSION file, or check the footer/admin panel of the Phorum interface for the version number.Affected if The version cannot be determined or shows a version <= 3.4.3
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Verify the Phorum web interface is accessibleAttempt to access the Phorum login or registration pages where user-submitted fields (subject line, author name, author email) are accepted. The vulnerability requires these input fields to be reachable.Affected if The posting/registration forms are publicly accessible or accessible to users
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Confirm the vulnerable input fields are enabledCheck Phorum configuration settings to verify that new post creation, user registration, or guest posting features are enabled. These features expose the vulnerable subject line, author name, and author email fields.Affected if Posting or registration forms allow user input in subject, author name, or author email fields
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Check if input sanitization is bypassedReview any available sanitization code or logs. The vulnerability specifically uses the '<<' pattern before a tag name to bypass XSS filters. If your logs show attempts with this pattern, the vulnerability is present.Affected if Input sanitization can be bypassed using the '<<' pattern in subject, author name, or author email fields
If Phorum version 3.4.3 or lower is installed and posting/registration forms are accessible, the environment is affected by this XSS vulnerability.
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 Phorum to version 3.4.3 or later to obtain the patched version that properly sanitizes user input in these fields.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2003-0283 — 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-2003-0283 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
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- 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