MoodleCMS
CVE-2024-28593
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 Chat activity in Moodle 4.3.3 allows students to insert a potentially unwanted HTML A element or IMG element, or HTML content that leads to a performance degradation. NOTE: the vendor's Using_Chat page says "If you know some HTML code, you can use it in your text to do things like insert images, play sounds or create different coloured and sized text." This page also says "Chat is due to be removed from standard Moodle."
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 · moderate confidenceThe Chat activity in Moodle 4.3.3 does not properly sanitize user-supplied input, allowing students to insert potentially malicious HTML A and IMG elements. This creates risks including phishing via arbitrary links, potential XSS if script execution is possible, and performance degradation from resource-heavy content like large embedded images.
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
= 4.3.3CVSS 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
- Unchanged
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/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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Identify your Moodle versionAccess the Moodle administration panel or check the version file in your Moodle installation directoryAffected if Your installed version is exactly 4.3.3
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Determine if the Chat activity is enabledNavigate to Site Administration > Plugins > Activity modules and verify if the Chat module is installed and visibleAffected if The Chat activity module is enabled and accessible to users
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Check if Chat is being used in any courseSearch for active Chat instances in your course list or check for recent Chat activity logsAffected if Any courses contain active Chat activities that users can access
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Assess the input handling configurationReview your Chat activity settings or message handling configuration for HTML sanitization controlsAffected if HTML sanitization is not enabled or configured for Chat messages
You are affected if your Moodle version is exactly 4.3.3 and the Chat activity is enabled and accessible to users 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 dataImplement input sanitization on Chat messages to strip or properly encode dangerous HTML elements (A with href, IMG tags), or disable the Chat activity entirely given its planned deprecation from Moodle.
Fix this in Moodle
Scoped from the published advisory
- Consultation6.0 h
- Implementation12.0 h
- Testing6.0 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 $7,680.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2024-28593 — 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-2024-28593 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
- No spam, self-promotion, credentials, or personal data