Avada (Fusion) Builder <= 3.15.2 - Unauthenticated Remote Code Execution via PHP Function Injection via 'render_logics' Shortcode Attribute via Widget AJAX Handler

MITRE NVD CVE.ORG JSON API Print: PDF PDF

Summary

CVECVE-2026-6279
StatePUBLISHED
AssignerWordfence
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-21 05:16:23 UTC
Updated2026-05-21 15:19:30 UTC
DescriptionThe 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.

Risk And Classification

Primary CVSS: v3.1 9.8 CRITICAL from [email protected]

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

EPSS: 0.001380000 probability, percentile 0.334580000 (date 2026-05-27)

Problem Types: CWE-74 | CWE-74 CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Themefusion Avada Fusion Builder affected 3.15.2 semver Not specified

References

ReferenceSourceLinkTags
www.wordfence.com/threat-intel/vulnerabilities/id/5dc72d78-d47c-4b36-8d69-8672e... [email protected] www.wordfence.com
plugins.trac.wordpress.org/browser/fusion-builder/tags/3.15.0/inc/helpers/class-fusion-b... [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/fusion-builder/trunk/inc/helpers/class-fusion-builder... [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/fusion-builder/trunk/shortcodes/fusion-widget.php [email protected] plugins.trac.wordpress.org
avada.com/documentation/avada-changelog [email protected] avada.com
plugins.trac.wordpress.org/browser/fusion-builder/trunk/inc/helpers/class-fusion-builder... [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/fusion-builder/tags/3.15.0/shortcodes/fusion-widget.php [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/fusion-builder/trunk/shortcodes/fusion-widget.php [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/fusion-builder/trunk/inc/class-fusion-builder.php [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/fusion-builder/tags/3.15.0/inc/helpers/class-fusion-b... [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/fusion-builder/tags/3.15.0/inc/class-fusion-builder.php [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/fusion-builder/tags/3.15.0/shortcodes/fusion-widget.php [email protected] plugins.trac.wordpress.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Tin Pham (en)

CNA: Trong Pham (en)

CNA: Hao Ngo (en)

Additional Advisory Data

SourceTimeEvent
CNA2026-04-15T07:44:24.000ZVendor Notified
CNA2026-05-20T15:45:14.000ZDisclosed
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