CVE-2020-12639
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 · uneditedphpList before 3.5.3 allows XSS, with resultant privilege elevation, via lists/admin/template.php.
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 confidencephpList before version 3.5.3 contains a cross-site scripting (XSS) vulnerability in the lists/admin/template.php file. An attacker can inject malicious JavaScript through this vector, which executes in the context of other admin users' sessions, potentially allowing privilege elevation from a lower-privileged admin account to full administrative access.
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< 3.5.3CVSS 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
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
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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Determine installed phpList versionCheck the version file in your phpList installation, typically found in the admin dashboard under 'System > About' or in a version.php file in the root directory.Affected if The installed version is lower than 3.5.3 (e.g., 3.5.2, 3.5.1, 3.4.x, etc.)
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Locate the vulnerable template.php fileVerify the existence of lists/admin/template.php in your phpList web root directory.Affected if The file exists and the phpList version is below 3.5.3
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Confirm admin interface accessibilityCheck if the phpList admin interface is accessible by visiting the /admin path on your web server.Affected if The admin panel is publicly or loosely accessible and the phpList version is below 3.5.3
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Review template.php for XSS vulnerability indicatorsInspect lists/admin/template.php for unsanitized user input handling, particularly around GET or POST parameters that might be reflected in the page output without proper encoding.Affected if The file contains parameters that are output without htmlspecialchars or equivalent encoding, and the version is below 3.5.3
You are affected if your phpList installation version is below 3.5.3 and the lists/admin/template.php file is present and accessible in your environment.
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 data3.5.3
Upgrade phpList to version 3.5.3 or later. Additionally, implement proper input validation and output encoding in template.php and related admin files to prevent XSS attacks.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,408.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-12639 — 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-2020-12639 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
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