CVE-2024-8618 is a medium-severity vulnerability classified as CWE-79 (Cross-Site Scripting, XSS) affecting the WordPress plugin 'Page Builder: Pagelayer' in versions prior to 1.9.0. The vulnerability arises because the plugin fails to properly sanitize and escape certain settings. This flaw allows users with high privileges, such as administrators, to inject and store malicious scripts within the plugin's settings. Notably, this attack vector remains viable even when the WordPress capability 'unfiltered_html' is disabled, which is commonly the case in multisite environments to restrict HTML input. The vulnerability requires high privilege (admin) access and user interaction to trigger the stored XSS payload, which can then execute in the context of other users viewing the affected pages or admin panels. The CVSS v3.1 score is 4.8 (medium), reflecting a network attack vector with low attack complexity, requiring high privileges and user interaction, and resulting in limited confidentiality and integrity impacts without affecting availability. No known exploits are currently reported in the wild, and no official patches or updates are linked yet, though upgrading to version 1.9.0 or later is implied to remediate the issue. This vulnerability could be leveraged to perform actions such as session hijacking, privilege escalation, or injecting malicious content, potentially compromising site administrators or users who access the affected pages or admin interfaces.

For European organizations using WordPress sites with the Page Builder: Pagelayer plugin, this vulnerability poses a risk primarily to site integrity and confidentiality. An attacker with admin privileges could inject malicious scripts that execute in other users' browsers, potentially stealing session cookies, performing unauthorized actions, or defacing content. In multisite WordPress setups, which are common in enterprise and educational institutions across Europe, the inability to rely on 'unfiltered_html' to block such attacks increases risk. While the vulnerability does not directly affect availability, the reputational damage and potential data leakage could be significant, especially for organizations handling sensitive or regulated data under GDPR. Attackers exploiting this vulnerability could gain footholds for further lateral movement or persistent access. However, the requirement for high privilege limits the attack surface to insiders or compromised admin accounts, reducing the likelihood of widespread exploitation but emphasizing the need for strong internal controls.

European organizations should immediately verify if their WordPress installations use the Page Builder: Pagelayer plugin and determine the version in use. Upgrading to version 1.9.0 or later, where the vulnerability is fixed, is the primary mitigation step. Until patched, restrict admin access strictly to trusted personnel and enforce strong authentication mechanisms such as multi-factor authentication (MFA) to reduce the risk of privilege abuse. Additionally, implement Content Security Policy (CSP) headers to limit the impact of potential XSS payloads. Regularly audit plugin settings and user inputs for suspicious content. For multisite environments, review and tighten capability assignments and consider additional input sanitization plugins or web application firewalls (WAFs) that can detect and block XSS attempts. Monitoring logs for unusual admin activity and conducting periodic security assessments of WordPress plugins will further reduce risk.