CVE-2026-54193 Overview
CVE-2026-54193 is an arbitrary file deletion vulnerability in the Fusion Builder WordPress plugin affecting versions up to and including 3.15.4. The flaw allows authenticated users holding Contributor-level privileges to delete arbitrary files on the WordPress host. The weakness is classified under [CWE-22] (Improper Limitation of a Pathname to a Restricted Directory), commonly known as path traversal. Successful exploitation can lead to denial of service, including site takeover when critical files such as wp-config.php are deleted, forcing WordPress into installation mode.
Critical Impact
An authenticated Contributor can delete arbitrary files on the server, enabling site disruption and potential takeover by removing wp-config.php.
Affected Products
- Fusion Builder WordPress plugin versions <= 3.15.4
- WordPress sites running vulnerable Fusion Builder releases
- Avada theme deployments bundling Fusion Builder <= 3.15.4
Discovery Timeline
- 2026-06-17 - CVE-2026-54193 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2026-54193
Vulnerability Analysis
The vulnerability resides in Fusion Builder's file handling logic, where user-supplied path input is processed without sufficient validation. A Contributor-level user can submit a crafted request that resolves to a file outside the plugin's intended working directory. The server then deletes the targeted file with the privileges of the web process. Because the scope is marked as changed in the CVSS vector, the impact extends beyond the plugin to the entire WordPress installation.
Root Cause
The root cause is improper limitation of a pathname to a restricted directory, classified as [CWE-22]. The plugin trusts a file path parameter supplied by an authenticated low-privilege user and passes it to a deletion routine without canonicalization or allowlist enforcement. Directory traversal sequences such as ../ are not stripped, allowing access to arbitrary locations within the filesystem accessible to the web server user.
Attack Vector
Exploitation requires an authenticated account with Contributor privileges or higher. The attacker issues a network request to the vulnerable Fusion Builder endpoint and supplies a manipulated file path parameter. No user interaction is required beyond the attacker's own session. Deleting wp-config.php is a notable attack path because WordPress reverts to the installation wizard, enabling the attacker to reconfigure the database connection and seize administrative control.
No public proof-of-concept code is available. Refer to the Patchstack Vulnerability Report for the disclosure details.
Detection Methods for CVE-2026-54193
Indicators of Compromise
- Unexpected deletion of files within the WordPress root, including wp-config.php, theme files, or plugin assets
- Sudden appearance of the WordPress installation wizard on a previously functional site
- HTTP POST requests to Fusion Builder AJAX endpoints from Contributor accounts containing ../ sequences in path parameters
- Web server logs showing file path parameters referencing locations outside /wp-content/uploads/
Detection Strategies
- Monitor WordPress audit logs for file deletion events originating from Contributor-level accounts
- Inspect access logs for Fusion Builder admin-ajax.php actions accompanied by path traversal patterns
- Alert on filesystem changes affecting WordPress core configuration files using file integrity monitoring
Monitoring Recommendations
- Enable a WordPress activity log plugin to capture user-attributed file operations
- Forward web server and WordPress logs to a centralized SIEM for correlation across sessions and IP addresses
- Track new Contributor account creation followed by unusual file operations within a short time window
How to Mitigate CVE-2026-54193
Immediate Actions Required
- Update the Fusion Builder plugin to a version newer than 3.15.4 once a patched release is available from the vendor
- Audit and remove unused Contributor-level accounts to reduce the exploitable user population
- Back up wp-config.php, the database, and the WordPress filesystem before patching
- Restrict Contributor registration on production sites where it is not operationally required
Patch Information
Review the Patchstack Vulnerability Report for the current patch status and upgrade guidance from the Fusion Builder maintainers.
Workarounds
- Apply a Web Application Firewall rule that blocks requests containing ../ or encoded traversal sequences in Fusion Builder parameters
- Set restrictive filesystem permissions so the web server user cannot delete wp-config.php or files outside wp-content/uploads/
- Temporarily disable the Fusion Builder plugin on sites where Contributor accounts cannot be removed
# Restrict write access on wp-config.php to mitigate deletion
chown root:www-data /var/www/html/wp-config.php
chmod 440 /var/www/html/wp-config.php
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
