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Joomla\!Application · Joomla

CVE-2026-21629

HIGH · 7.3 CVSS v3.1 Published 2026-04-01
Fix available
A fix is available. Upgrade to 5.4.4 / 6.0.4 or later.
See remediation →
82/100
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
The ajax component was excluded from the default logged-in-user check in the administrative area. This behavior was potentially unexpected by 3rd party developers.

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

The ajax component in the administrative area lacks the default logged-in-user authentication check that other admin components enforce. This could allow unauthenticated access to administrative AJAX functionality.

MitigationApply the same logged-in-user authentication check to the ajax component that is used by other administrative area components.

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
Joomla\!Application
Affected:>= 3.0.0, < 5.4.4>= 6.0.0, < 6.0.4

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

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

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 Joomla version
    Check your Joomla installation's version number in the administrator panel (Help > System Information > Joomla! Version) or in the libraries/cms.php version file
    Affected if The installed version falls within >= 3.0.0, < 5.4.4 or >= 6.0.0, < 6.0.4
  2. Locate the ajax admin component
    Navigate to the /administrator/components/ directory and identify the com_ajax component folder if present
    Affected if The com_ajax component exists in the administrative components directory
  3. Verify authentication enforcement in ajax component
    Examine the main entry point file (typically controller.php or services/provider.php) within the com_ajax component for a logged-in-user authentication check
    Affected if No authentication check (such as $app->isAdmin() combined with user session verification) is present in the component's entry point
  4. Test unauthenticated ajax endpoint access
    Attempt to access an admin ajax endpoint (such as /administrator/index.php?option=com_ajax&format=json) without logging in
    Affected if The request returns a valid response instead of redirecting to the login page or returning an authentication error

You are affected if your Joomla version is 3.0.0 through 5.4.3 or 6.0.0 through 6.0.3 AND the ajax component accepts requests without requiring authentication.

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 5.4.4 / 6.0.4 or later
Fixed in 5.4.46.0.4
Interim mitigation

Apply the same logged-in-user authentication check to the ajax component that is used by other administrative area components.

Recommended fix High confidence

Joomla! 5.4.4 or Joomla! 6.0.4 (depending on your current major version branch)

  1. 1. Backup your Joomla! database and files before proceeding with any upgrade
  2. 2. Navigate to the Joomla! Administrator dashboard
  3. 3. Go to System > Update > Joomla! or use Components > Joomla! Update
  4. 4. Click the 'Install the update' button to apply the latest Joomla! update that includes the fix
  5. 5. Alternatively, download Joomla! 5.4.4 (for 5.x sites) or Joomla! 6.0.4 (for 6.x sites) from the official Joomla! downloads page
  6. 6. Upload and install the updated package through Extensions > Install
  7. 7. Clear any caching systems and verify the administrator area is accessible
  8. 8. Test that the ajax component now properly enforces the logged-in-user check in the administrative area
Caveat Upgrading across major Joomla! versions (e.g., 3.x to 5.x, or 5.x to 6.x) may introduce breaking changes in extensions, templates, or custom code; test thoroughly in a staging environment first

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

Fix this in Joomla\! Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.

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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-2026-21629 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