Attack Chain

1. An unauthenticated attacker identifies a WordPress site using a vulnerable version of the Piotnet Addons for Elementor Pro plugin (<= 7.1.70) and with a form that includes a file upload field.
2. The attacker crafts a malicious file with a dangerous extension such as .phar or .phtml. This file contains malicious PHP code designed to execute commands on the server.
3. The attacker sends an HTTP POST request to the WordPress site’s endpoint associated with the pafe_ajax_form_builder function, including the crafted malicious file in the file upload field.
4. Due to the incomplete blacklist, the server accepts the file with the .phar or .phtml extension and saves it to the WordPress uploads directory.
5. The attacker determines the full path to the uploaded file. This may involve brute-forcing or leveraging other vulnerabilities to disclose file paths.
6. The attacker sends an HTTP request to the uploaded malicious file. The web server processes the file as PHP code due to the .phar or .phtml extension.
7. The malicious PHP code executes, allowing the attacker to execute arbitrary commands on the server.
8. The attacker gains control of the web server, potentially escalating privileges to compromise the entire system.

Impact

Successful exploitation of CVE-2026-4885 allows unauthenticated attackers to upload arbitrary files to vulnerable WordPress sites running the Piotnet Addons for Elementor Pro plugin (<= 7.1.70). This can lead to remote code execution, allowing attackers to gain complete control of the web server and potentially the entire system. Attackers can then steal sensitive data, deface the website, or use the compromised server as a launchpad for further attacks.

Recommendation

• Upgrade the Piotnet Addons for Elementor Pro plugin to a version greater than 7.1.70 to patch CVE-2026-4885.
• Implement the Sigma rule Detect CVE-2026-4885 Exploitation — Malicious File Upload via Piotnet Addons to identify attempts to upload files with dangerous extensions.
• Monitor web server logs for HTTP requests to .phar or .phtml files within the WordPress uploads directory, as detected by the Sigma rule Detect Access to Suspicious PHP Files in Uploads Directory.
• Consider implementing web application firewall (WAF) rules to block file uploads with suspicious extensions.