CVE-2026-1543 — Cross-Site Scripting (XSS)

title: Avada Builder Stored XSS via Shortcode Injection — CVE-2026-1543
id: scw-2026-05-21-ai-1
status: experimental
level: high
description: |
  Detects attempts to exploit CVE-2026-1543 by injecting script tags within the fusion_builder_shortcode parameter in the Avada Builder plugin's AJAX endpoint. This indicates a Stored Cross-Site Scripting attack targeting WordPress sites using vulnerable versions of the Avada Builder plugin.
author: SCW Feed Engine (AI-generated)
date: 2026-05-21
references:
  - https://shimiscyberworld.com/posts/nvd-CVE-2026-1543/
tags:
  - attack.initial_access
  - attack.t1190
logsource:
    category: webserver
detection:
  selection:
      cs-uri|contains:
          - '/wp-admin/admin-ajax.php'
      cs-uri-query|contains:
          - 'action=fusion_builder_ajax'
      cs-uri-query|contains:
          - 'fusion_builder_shortcode'
      cs-uri-query|contains:
          - '<script>'
      cs-uri-query|contains:
          - 'alert('
  condition: selection
falsepositives:
  - Legitimate administrative activity

Source: Shimi's Cyber World · License & reuse