dbcve.org
InjectionWeakness · CWE-74

CVE-2026-6279

CRITICAL · 9.8 CVSS v3.1 Published 2026-05-21
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
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 Avada Builder (fusion-builder) plugin for WordPress is vulnerable to Unauthenticated Remote Code Execution via PHP Function Injection in versions up to and including 3.15.2. This is due to the `wp_conditional_tags` case in `Fusion_Builder_Conditional_Render_Helper::get_value()` passing attacker-controlled values from a base64-decoded JSON blob directly to `call_user_func()` without any allowlist validation. This is exploitable by unauthenticated attackers through the `fusion_get_widget_markup` AJAX endpoint, which is registered for non-privileged (unauthenticated) users via `wp_ajax_nopriv_fusion_get_widget_markup`. The endpoint is protected only by a nonce (`fusion_load_nonce`), but this nonce is generated for user ID 0 and is deterministically exposed in the JavaScript output of any public-facing page containing a Post Cards (`[fusion_post_cards]`) or Table of Contents (`[fusion_table_of_contents]`) element. This makes it possible for unauthenticated attackers to execute arbitrary code on affected sites.

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 Avada Builder plugin for WordPress contains an unauthenticated RCE vulnerability in versions up to 3.15.2. Attackers exploit the `fusion_get_widget_markup` AJAX endpoint by passing a base64-encoded JSON blob to `Fusion_Builder_Conditional_Render_Helper::get_value()`, which directly passes user-controlled data to `call_user_func()` without allowlist validation. The required nonce is deterministically exposed in public JavaScript output of pages using Post Cards or Table of Contents elements.

MitigationUpdate the Avada Builder plugin to a version newer than 3.15.2 when available. Until the patch is released, consider disabling the plugin, restricting the AJAX endpoint via web server rules, or implementing additional access controls.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

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
High
Availability
High

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

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. Verify Avada Builder plugin is installed
    In WordPress admin, go to Plugins > Installed Plugins and locate the 'Avada Builder' (fusion-builder) plugin. Note the installed version number.
    Affected if The plugin is installed and the version is 3.15.2 or earlier, or if the version cannot be determined.
  2. Confirm the vulnerable AJAX endpoint exists
    Check if the file wp-content/plugins/fusion-builder/ajax.php or similar endpoint handlers exist and are accessible. Alternatively, test for the existence of the wp_ajax_nopriv_fusion_get_widget_markup action by inspecting the plugin's AJAX registration code in fusion-builder.php or ajax.php.
    Affected if The plugin has the fusion_get_widget_markup AJAX action registered for unauthenticated (nopriv) users.
  3. Identify if Post Cards or Table of Contents elements are in use
    Search the WordPress database or inspect page content for instances of fusion_toc, fusion_post_card, or related Avada shortcodes/widgets. Check public-facing pages containing these elements, as they expose the fusion_load_nonce in their JavaScript.
    Affected if Public pages contain Post Cards, Table of Contents, or similar Avada elements that load the fusion_load_nonce in client-side JavaScript.
  4. Check nonce exposure in page source
    View the source HTML of a public page using Avada Builder elements. Search for 'fusion_load_nonce' in script tags. If found, note that this nonce is generated for user ID 0 and is deterministic.
    Affected if The fusion_load_nonce is exposed in public page JavaScript, making it predictable and reusable.

If the Avada Builder plugin version is 3.15.2 or earlier and public pages contain Post Cards or Table of Contents elements that expose the fusion_load_nonce, the site is vulnerable to unauthenticated RCE via the wp_ajax_nopriv_fusion_get_widget_markup 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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update the Avada Builder plugin to a version newer than 3.15.2 when available. Until the patch is released, consider disabling the plugin, restricting the AJAX endpoint via web server rules, or implementing additional access controls.

Recommended fix High confidence

Latest version of Avada Builder (fusion-builder) plugin after 3.15.2 - check WordPress plugin repository for the current stable release

  1. 1. Check the current version of the Avada Builder (fusion-builder) plugin installed on your WordPress site.
  2. 2. Navigate to Plugins > Installed Plugins in the WordPress admin dashboard.
  3. 3. If the installed version is 3.15.2 or lower, update the Avada Builder plugin to the latest available version.
  4. 4. Alternatively, you can update via WordPress admin notifications or by downloading the latest version from the WordPress plugin repository.
  5. 5. After updating, verify the site functions correctly and test the Post Cards and Table of Contents elements to ensure the fix is working.
Caveat Review Avada plugin changelog for any breaking changes between 3.15.2 and the target version; major version jumps may include template/element changes

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

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,970
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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-2026-6279 in production — separate from our analysis above.

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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