CVE-2026-1499 is a critical security vulnerability found in the WP Duplicate – WordPress Migration Plugin, versions up to and including 1.1.8. The root cause is a missing authorization check on the AJAX action process_add_site(), which allows authenticated users with subscriber-level privileges to set an internal option named prod_key_random_id. This internal state manipulation can then be exploited by unauthenticated attackers to bypass authentication mechanisms. The vulnerability is further exacerbated by a path traversal flaw in the file upload functionality handled by the handle_upload_single_big_file() function. Together, these issues enable attackers to upload arbitrary files to the server, potentially leading to remote code execution (RCE). The CVSS v3.1 base score is 9.8, reflecting the vulnerability’s high impact on confidentiality, integrity, and availability, and its ease of exploitation without user interaction or elevated privileges. Although no known exploits have been reported in the wild yet, the combination of missing authorization and path traversal in a widely used WordPress plugin presents a significant risk. The vulnerability could be exploited to compromise websites, steal sensitive data, deface sites, or deploy malware. The lack of a patch at the time of disclosure necessitates immediate mitigation steps to reduce exposure. This vulnerability highlights the critical importance of proper authorization checks in AJAX endpoints and secure handling of file uploads in WordPress plugins.

For European organizations, the impact of CVE-2026-1499 can be severe, particularly for those relying on WordPress websites with the WP Duplicate plugin installed. Successful exploitation can lead to full server compromise, allowing attackers to execute arbitrary code, steal sensitive customer or business data, deface websites, or use the compromised server as a pivot point for further attacks within the network. This can result in significant operational disruption, reputational damage, regulatory penalties under GDPR for data breaches, and financial losses. Public-facing websites, e-commerce platforms, and government portals using this plugin are especially vulnerable. The vulnerability’s ability to be exploited without elevated privileges or user interaction increases the attack surface and likelihood of exploitation. Given the critical nature of the flaw, organizations may face targeted attacks aiming to exploit this vulnerability for espionage, ransomware deployment, or service disruption. The absence of known exploits in the wild currently provides a window for proactive defense, but the risk remains high due to the plugin’s popularity and the severity of the flaw.

1. Immediately restrict access to the AJAX endpoint process_add_site() by implementing web application firewall (WAF) rules or server-level access controls to block unauthorized or subscriber-level requests. 2. Monitor web server logs and WordPress activity logs for unusual file upload attempts or changes to the prod_key_random_id option. 3. Disable or uninstall the WP Duplicate plugin if it is not essential to reduce the attack surface until a patch is available. 4. Apply vendor patches or updates as soon as they are released to address the missing authorization and path traversal issues. 5. Harden WordPress installations by enforcing least privilege principles, ensuring users have only necessary permissions. 6. Implement file integrity monitoring to detect unauthorized file uploads or modifications. 7. Conduct regular security audits and vulnerability scans focusing on WordPress plugins and their configurations. 8. Educate site administrators about the risks of installing unverified plugins and the importance of timely updates. 9. Use security plugins that can detect and block suspicious AJAX requests and file uploads. 10. Consider isolating WordPress environments in segmented network zones to limit potential lateral movement in case of compromise.