Frontend Login and Registration Blocks - Privilege Escalation (CVE-2025-3605)

CVE-2025-3605 is a critical vulnerability in the Frontend Login and Registration Blocks plugin for WordPress that allows unauthenticated attackers to escalate privileges by taking over user accounts, including those of administrators. By exploiting improper identity validation in the plugin, attackers can change any user's email address and subsequently reset their password, leading to full account compromise and potential site takeover.

CrowdSec has been tracking this vulnerability and its exploits since 24th of September 2025.

Based on data from the CrowdSec network, nearly all observed exploitation of CVE-2025-3605 is fully opportunistic, with attackers indiscriminately scanning the entire internet. These attacks are automated and lack any form of target selection or reconnaissance. CrowdSec network telemetry also shows that exploitation of CVE-2025-3605 has significantly declined over the past week. Attack volumes are well below the long-term average, suggesting attackers are rapidly losing interest. The vulnerability appears to be falling out of active use across most threat landscapes.

Attackers exploit the AJAX endpoint /wp-admin/admin-ajax.php by sending requests with the action=flrblocksusersettingsupdatehandle parameter to change the administrator's email address, enabling privilege escalation through the password reset process.