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MoodleCMS

CVE-2025-67853

HIGH · 7.5 CVSS v3.1 Published 2026-02-03
Fix available
A fix is available. Upgrade to 4.1.22 / 4.4.11 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges 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. A remote attacker could exploit a lack of proper rate limiting in the confirmation email service. This vulnerability allows attackers to more easily enumerate or guess user credentials, facilitating brute-force attacks against user accounts.

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 confirmation email service lacks proper rate limiting, allowing remote attackers to repeatedly submit email addresses to determine which ones are registered in the system. This user enumeration enables credential guessing and facilitates brute-force attacks.

MitigationImplement rate limiting on the email confirmation endpoint to restrict the number of requests from a single source within a time window, potentially combined with CAPTCHA or account lockout policies.

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:< 4.1.22>= 4.4.0, < 4.4.11>= 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
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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. Identify installed Moodle version
    Access the admin interface, navigate to Site Administration > Server > Environment, or check the version.php file in the Moodle root directory (look for $version or $release variables)
    Affected if The installed version falls in any of these ranges: < 4.1.22, >= 4.4.0 and < 4.4.11, >= 4.5.0 and < 4.5.8, >= 5.0.0 and < 4.0.4, or equals 5.1.0
  2. Verify email self-registration is enabled
    Go to Site Administration > Plugins > Authentication > Manage Authentication, and check if 'Email-based self-registration' (or similar self-registration option) is set to enabled
    Affected if Email self-registration is enabled and the installed version is vulnerable (see step 1)
  3. Confirm the confirmation email endpoint is exposed
    Attempt to access the password reset or new account confirmation endpoint (typically /login/forgot_password.php or /login/signup.php) without authentication, or check if these scripts are accessible to unauthenticated users
    Affected if Unauthenticated users can access the email confirmation or password reset form, and the installed version is vulnerable
  4. Check for rate limiting on email endpoints
    Review web server (Apache/Nginx) configuration or Moodle settings for rate limiting rules on /login/forgot_password.php, /login/signup.php, or adjacent endpoints. Also check if any WAF or traffic management tool is applying rate limits to these paths
    Affected if No rate limiting, CAPTCHA, or account lockout mechanism is configured for the email confirmation endpoint, and the installed version is vulnerable

A user is affected if their Moodle version is in the affected ranges AND email self-registration or password reset is enabled with no rate limiting on the confirmation endpoint.

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 4.1.22 / 4.4.11 / 4.5.8 or later
Fixed in 4.1.224.4.114.5.8
Interim mitigation

Implement rate limiting on the email confirmation endpoint to restrict the number of requests from a single source within a time window, potentially combined with CAPTCHA or account lockout policies.

Recommended fix High confidence

Moodle 4.1.22, 4.4.11, 4.5.8, or 5.0.4 (depending on your current branch)

  1. 1. Back up your Moodle database and entire Moodle directory (codebase, moodledata, and any custom plugins)
  2. 2. Identify your current Moodle version branch (4.1.x, 4.4.x, 4.5.x, or 5.0.x)
  3. 3. Download the corresponding fixed version: 4.1.22 for 4.1.x, 4.4.11 for 4.4.x, 4.5.8 for 4.5.x, or 5.0.4 for 5.0.x from moodle.org
  4. 4. Replace the Moodle codebase with the new version files
  5. 5. Run the Moodle upgrade script via CLI (php admin/cli/upgrade.php) or through the web interface
  6. 6. Clear all Moodle caches (php admin/cli/purge_caches.php)
  7. 7. Verify the rate limiting is now properly enforced on the user confirmation email functionality
Caveat Standard Moodle upgrade risks apply - test in staging first, ensure custom plugins are compatible with the target version, and verify all functionality post-upgrade

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
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,560.

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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-2025-67853 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