MoodleCMS
CVE-2011-4301
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 · uneditedThe MoodleQuickForm class in the Forms Library in lib/formslib.php in Moodle 1.9.x before 1.9.14, 2.0.x before 2.0.5, and 2.1.x before 2.1.2 does not recognize Forms API setConstant operations, which allows remote attackers to submit unexpected form content by modifying the values of constant fields.
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 confidenceThe MoodleQuickForm class in lib/formslib.php fails to properly enforce 'setConstant' operations in the Forms API, allowing remote attackers to submit and modify values for fields that should be immutable (constant). This enables form manipulation where attackers can override server-defined constant field values.
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
MoodleCMS
= 1.9.2= 1.9.3= 1.9.4= 1.9.5= 1.9.6= 1.9.7= 1.9.8= 1.9.9= 1.9.10= 1.9.11= 1.9.12= 1.9.13CVSS 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
- Authentication
- None
- Confidentiality
- None
- Integrity
- Partial
- Availability
- None
AV:N/AC:L/Au:N/C:N/I:P/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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Check Moodle versionLocate the version.php file in your Moodle installation (usually in version.php at the root or in lib/ directory) and read the $release or $version variable to determine the installed versionAffected if The installed version is between 1.9.2 and 1.9.13 inclusive
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Locate the vulnerable library fileVerify that lib/formslib.php exists in your Moodle installation and note its file modification dateAffected if The file exists and the Moodle version falls within the affected range
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Identify forms using setConstantSearch your Moodle codebase for uses of the setConstant method (grep -r 'setConstant' or similar) to find any custom forms that define constant fieldsAffected if Any form definition uses setConstant to define immutable fields and the Moodle version is in the affected range
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Review form processing behaviorExamine how your forms handle submitted data - specifically check if form validation properly rejects client-submitted values for fields declared as constantsAffected if The Forms API allows submitted values to override constant field definitions
You are affected if running Moodle version 1.9.2 through 1.9.13 and using forms with setConstant-defined fields that should be immutable but can be manipulated by users.
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 to Moodle 1.9.14, 2.0.5, 2.1.2 or later which contain the fix for proper validation of constant fields in the Forms Library.
Fix this in Moodle
Scoped from the published advisory
- Consultation1.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,664.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2011-4301 — 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-2011-4301 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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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
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