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MoodleCMS

CVE-2024-45691

MEDIUM · 5.4 CVSS v3.1 Published 2024-11-20
Fix available
A fix is available. Upgrade to 4.1.13 / 4.2.10 or later.
See remediation →
60/100
Remediation priority · Elevated
Remotely reachable Zero-click

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. When restricting access to a lesson activity with a password, certain passwords could be bypassed or less secure due to a loose comparison in the password-checking logic. This issue only affected passwords set to "magic hash" values.

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

Moodle's lesson activity module uses loose comparison (==) instead of strict comparison (===) when verifying passwords set for access restriction. When a password is set to certain 'magic hash' values (hash strings that evaluate to '0' in loose PHP comparisons), the password check can be bypassed, allowing unauthorized access to the protected lesson content.

MitigationUpgrade to a patched Moodle version that implements strict comparison for password verification in the lesson module. Until then, avoid using password protection on lesson activities or ensure passwords are not set to values that could act as magic hashes.

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:< 4.1.13>= 4.2.0, < 4.2.10>= 4.3.0, < 4.3.7>= 4.4.0, < 4.4.3

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/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 checks

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

  1. Check installed Moodle version
    Navigate to Site Administration > Server > Environment or check the version.php file in the Moodle root directory (look for $release or $version variables)
    Affected if The installed version falls within < 4.1.13, >= 4.2.0 and < 4.2.10, >= 4.3.0 and < 4.3.7, or >= 4.4.0 and < 4.4.3
  2. Determine if lesson activity module is in use
    Check if the lesson module is installed and enabled by reviewing Site Administration > Plugins > Activity modules > Manage activities, or query the 'mdl_modules' database table for the 'lesson' entry where 'visible' = 1
    Affected if The lesson module is installed and visible on the site
  3. Identify lessons with password protection enabled
    Query the database: SELECT id, course, name FROM mdl_lesson WHERE password != ''; or inspect individual lesson settings under 'Restrict access' > 'Password' field in the lesson editing interface
    Affected if Any lesson activities have a non-empty password value set for access restriction
  4. Inspect password verification code for loose comparison
    Examine the file mod/lesson/locallib.php (or mod/lesson/access.php) around the password verification logic. Search for patterns like 'if ($password == ...)' or 'if (md5($input) == $stored)' rather than strict comparison '==='
    Affected if The code uses loose comparison (==) instead of strict comparison (===) when validating passwords
  5. Review actual password values for magic hash patterns
    If database access is available, examine the password field in mdl_lesson table. Look for hash strings that evaluate to '0' in PHP loose comparisons (certain MD5/SHA hashes starting with specific hex patterns)
    Affected if Any lesson password is set to a value that would evaluate to '0' via loose PHP comparison (magic hash)

A user is affected if their Moodle version is within the affected ranges AND they have lesson activities with password protection enabled using a vulnerable code version.

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 4.1.13 / 4.2.10 / 4.3.7 or later
Fixed in 4.1.134.2.104.3.7
Interim mitigation

Upgrade to a patched Moodle version that implements strict comparison for password verification in the lesson module. Until then, avoid using password protection on lesson activities or ensure passwords are not set to values that could act as magic hashes.

Recommended fix High confidence

Upgrade to Moodle 4.1.13, 4.2.10, 4.3.7, or 4.4.3 (choose the release matching your current branch)

  1. 1. Back up your Moodle database and code directory before proceeding with any upgrade
  2. 2. Identify your current Moodle version by checking /lib/upgrade.txt or the admin interface
  3. 3. Download the appropriate fixed version from moodle.org/downloads matching your branch (4.1.13, 4.2.10, 4.3.7, or 4.4.3)
  4. 4. Put your Moodle site into maintenance mode via Site Administration > Server > Maintenance Mode
  5. 5. Replace your Moodle code directory with the new version files, preserving config.php and any local customizations
  6. 6. Run the Moodle upgrade script by visiting your site URL
  7. 7. Clear all Moodle caches via Site Administration > Development > Purge caches
  8. 8. Verify the fix by testing lesson activity password protection with various password values
Caveat Major Moodle upgrades may require theme and plugin updates; test in staging first

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

Fix this in Moodle Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA2.0 h
9.0 hours of engineering $1,570
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,512.

Scan for this in your stack

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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-2024-45691 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