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MoodleCMS

CVE-2025-67849

MEDIUM · 6.1 CVSS v3.1 Published 2026-02-03
Fix available
A fix is available. Upgrade to 4.5.8 / 5.0.4 or later.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

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 · unedited
A flaw was found in Moodle. This cross-site scripting (XSS) vulnerability, caused by improper sanitization of AI prompt responses, allows attackers to inject malicious HTML or script into web pages. When other users view these compromised pages, their sessions could be stolen, or the user interface could be manipulated.

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 confidence

Moodle fails to properly sanitize AI prompt responses before displaying them in the web interface, allowing attackers to inject malicious HTML or JavaScript that executes in other users' browsers. This is a stored XSS vulnerability where the malicious payload originates from AI-generated content and persists for users who view the compromised pages.

MitigationImplement proper output encoding and sanitization for all AI prompt responses before rendering in the web UI, following Moodle's existing XSS prevention patterns.

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
Affected:>= 4.5.0, < 4.5.8>= 5.0.0, < 5.0.4= 5.1.0

CVSS 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 checks

Work through these to decide whether this CVE applies to you.

  1. Check your Moodle version
    Navigate to Site Administration > Server > Environment or check the version.php file in your Moodle root directory. Run: grep '$version' version.php | head -5
    Affected if The installed version is >= 4.5.0 and < 4.5.8, OR >= 5.0.0 and < 5.0.4, OR = 5.1.0
  2. Verify AI module is enabled
    Go to Site Administration > Plugins > Manage plugins and search for AI-related plugins (AI Assistant, AI Pool, or similar). Check if any AI plugins are installed and enabled.
    Affected if Any AI plugin or AI assistant feature is enabled and configured for use
  3. Identify AI response storage locations
    Examine the database tables for AI-related content: look for tables prefixed with 'ai_' or containing 'prompt'/'response' in the mdl_ prefix database. Use: SHOW TABLES LIKE '%ai%' or SHOW TABLES LIKE '%prompt%'
    Affected if AI prompt response data exists in the database from user interactions
  4. Inspect AI output rendering points
    Search the codebase for files that render AI responses in the web UI. Look for templates or renderers handling AI content output, typically in lib/ or mod/ai/ directories.
    Affected if AI response content is rendered without visible sanitization checks (look for 'format_text', 's', or 'purify' functions applied to AI output)

You are affected if your Moodle version falls within the affected ranges AND the AI module/feature is enabled and being used to generate and display AI responses in the web interface.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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.

dbcve · scoped
Upgrade available Upgrade to 4.5.8 / 5.0.4 or later
Fixed in 4.5.85.0.4
Interim mitigation

Implement proper output encoding and sanitization for all AI prompt responses before rendering in the web UI, following Moodle's existing XSS prevention patterns.

Recommended fix High confidence

Moodle 4.5.8 (for 4.5.x branches) OR Moodle 5.0.4 (for 5.0.x branches) OR Moodle 5.1.1+ (for 5.1.0)

  1. 1. Backup your Moodle database and all site files before proceeding
  2. 2. Place your Moodle site into maintenance mode via Site administration > Server > Maintenance mode
  3. 3. Download the appropriate fixed Moodle version from the official Moodle downloads page (moodle.org)
  4. 4. Extract the new Moodle files and replace your existing installation files
  5. 5. Run the Moodle upgrade script by accessing your site URL (e.g., yourmoodlesite.com/admin/index.php)
  6. 6. Follow the on-screen upgrade instructions to complete the database migration
  7. 7. Clear all Moodle caches after upgrade completes
  8. 8. Verify the AI prompt functionality works correctly and test that XSS is mitigated
Caveat Review the specific release notes for your target version; major Moodle upgrades between branches (e.g., 4.x to 5.x) may have feature changes or deprecations

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Moodle Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-67849 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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