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MoodleCMS

CVE-2024-33996

MEDIUM · 6.2 CVSS v3.1 Published 2024-05-31
Fix available
A fix is available. Upgrade to 4.1.10 / 4.2.7 or later.
See remediation →
66/100
Remediation priority · Elevated
Remotely reachable

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
Incorrect validation of allowed event types in a calendar web service made it possible for some users to create events with types/audiences they did not have permission to publish to.

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 confidence

The calendar web service has insufficient validation of allowed event types, allowing authenticated users to create events with types or audiences they lack permissions to publish to. This is an authorization bypass where the permission check can be circumvented.

MitigationImplement robust server-side validation that enforces permission checks before event creation, and audit existing events for any created with unauthorized types/audiences.

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:< 4.1.10>= 4.2.0, < 4.2.7>= 4.3.0, < 4.3.4

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
High
User interaction
Required
Scope
Changed
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:N/I:H/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. Determine Moodle installed version
    Navigate to Site administration > Server > Environment, or check /lib/version.php for the $release or $version variable
    Affected if Version is < 4.1.10 OR (>= 4.2.0 AND < 4.2.7) OR (>= 4.3.0 AND < 4.3.4)
  2. Verify Calendar web service is enabled
    Navigate to Site administration > Plugins > Web services > Manage protocols. Check if any protocol (REST, SOAP, XML-RPC) is enabled
    Affected if At least one web service protocol is enabled
  3. Confirm Calendar external service is exposed
    Navigate to Site administration > Plugins > Web services > External services. Look for a service that includes calendar functions (such as core_calendar_create_event)
    Affected if An external service exposing calendar functions exists and is enabled
  4. Check if authenticated users can access the web service
    Navigate to Site administration > Plugins > Web services > Manage tokens. Review which users or roles have API tokens, or check Site administration > Plugins > Web services > Manage protocols for allowed user roles
    Affected if Authenticated (non-admin) users have web service access tokens or are permitted to use enabled protocols
  5. Inspect recent calendar events for anomalous types or audiences
    Run database query: SELECT * FROM mdl_event WHERE eventtype NOT IN ('user', 'site', 'course', 'group') OR audience NOT IN (1,2) LIMIT 100; Or use Site administration > Calendar > Manage calendars to review event visibility settings
    Affected if Events exist with unexpected eventtype values or audience settings that standard users should not be able to create

If your Moodle version falls within the affected ranges AND the calendar web service is exposed to authenticated users, your environment may be vulnerable to unauthorized event creation.

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 4.1.10 / 4.2.7 / 4.3.4 or later
Fixed in 4.1.104.2.74.3.4
Interim mitigation

Implement robust server-side validation that enforces permission checks before event creation, and audit existing events for any created with unauthorized types/audiences.

Recommended fix High confidence

Moodle 4.1.10+ (for 4.1.x users), 4.2.7+ (for 4.2.x users), or 4.3.4+ (for 4.3.x users)

  1. Confirm your current Moodle version by checking the version.php file in the Moodle root directory
  2. Create a complete backup of your Moodle database and the moodledata directory
  3. Create a backup of your Moodle source code directory
  4. Download the appropriate fixed Moodle version from moodle.org (4.1.10, 4.2.7, or 4.3.4)
  5. Replace the old Moodle source files with the new version, preserving your config.php file
  6. Run the upgrade process by accessing the site via browser (e.g., https://yourmoodle.com)
  7. Follow any additional upgrade instructions in the Moodle release notes
  8. Verify the upgrade was successful by checking the admin page shows the new version number
Caveat Standard Moodle upgrade caveats apply - review the Moodle release notes for your target version for any behavior changes or deprecations

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

Fix this in Moodle Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing5.0 h
  • Review / QA3.0 h
17.0 hours of engineering $2,970
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,752.

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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-2024-33996 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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