Attack Chain

1. An unauthenticated attacker crafts a malicious Cross-Site Request Forgery (CSRF) payload designed to target the vulnerable setCustomText function of the Salon Booking System plugin.
2. The attacker socially engineers an authenticated administrator of the target WordPress site to click on a crafted link (e.g., via phishing email or malicious website).
3. The administrator's browser, authenticated to the WordPress site, sends the forged POST request containing the malicious PHP code as part of the 'value' parameter.
4. Due to the absence of proper nonce validation, the WordPress site processes the request as legitimate, invoking the vulnerable setCustomText function.
5. The setCustomText function, which uses sanitize_text_field() on the 'value' parameter, fails to adequately neutralize PHP metacharacters within the attacker-supplied input.
6. The unneutralized arbitrary PHP code is then interpolated into a string literal and written to the translate-constants.php file within the plugin's directory via file_put_contents().
7. The attacker then directly accesses the now-modified and web-accessible translate-constants.php file, causing the injected PHP code to execute on the server.
8. Remote Code Execution (RCE) is achieved, granting the attacker control over the compromised WordPress server.

Impact

Successful exploitation of CVE-2026-15070 allows unauthenticated attackers to achieve remote code execution on the compromised WordPress server. This can lead to complete compromise of the website and underlying server, including data theft, defacement, installation of malware, establishment of persistent backdoors, and further network infiltration. The severity of the impact is high, as an attacker gaining RCE can fully control the affected system, affecting all data and services hosted on it. There are no specific victim counts or sectors mentioned, but any organization using the vulnerable plugin is at risk.

Recommendation

• Immediately update the Salon Booking System - Free Version plugin for WordPress to a version patched against CVE-2026-15070 (version 10.30.33 or later).
• Deploy the provided Sigma rule to your webserver logs to detect attempts to exploit CVE-2026-15070.
• Configure web application firewalls (WAFs) to block requests to /wp-admin/admin-ajax.php that contain common PHP code injection patterns in POST parameters.