Popup Builder - XSS (CVE-2023-6000)

CVE-2023-6000 is a vulnerability in the Popup Builder WordPress plugin prior to version 4.2.3 that allows unauthenticated visitors to modify existing popups and inject arbitrary JavaScript, resulting in stored cross-site scripting (XSS) attacks. This flaw could enable attackers to execute malicious scripts in the browsers of site visitors, potentially leading to data theft or session hijacking.

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-2023-6000 is fully opportunistic, with attackers indiscriminately scanning the entire internet. These attacks are automated and lack any form of target selection or reconnaissance. Telemetry from the CrowdSec network also shows that exploitation activity for CVE-2023-6000 remains steady week-over-week. Attack volumes are consistent with long-term trends, indicating sustained interest from threat actors. CVE-2023-6000 continues to be an active part of the threat landscape and will likely remain this way for the forseeable future.

Attackers exploit the Popup Builder plugin by sending unauthenticated POST requests to the WordPress root endpoint with parameters like sgpb-is-preview, post_ID, and sgpb-WillOpen containing malicious JavaScript, resulting in stored XSS on vulnerable sites.