The plugin contains a stored cross‑site scripting flaw that allows an authenticated contributor or higher to inject arbitrary JavaScript via the 'sg_popup' shortcode. Because the plugin fails to properly sanitize and escape user supplied attributes, the malicious script is persisted in the database and executed whenever any visitor renders the compromised popup. This can lead to defacement, credential theft, and further compromise of site integrity.

Any WordPress installation running the Popup Builder – Create highly converting, mobile friendly marketing popups. plugin version 4.4.1 or earlier is affected. The vulnerability exists in all releases through 4.4.1; upgrading beyond 4.4.1 removes the flaw.

The likely attack vector is an authenticated contributor or higher user in WordPress who can edit popups. The attacker can inject malicious code into the sg_popup shortcode, which is then stored and executed for all site visitors. The CVSS score of 6.4 indicates moderate impact; the EPSS score of less than 1% suggests a low likelihood of exploitation in the wild, though the persistence of the flaw means that any site using an affected version remains vulnerable until the plugin is updated. The vulnerability is not listed in CISA’s KEV catalog.