CVE-2024-7556 is a medium severity vulnerability classified as CWE-79 (Cross-Site Scripting, XSS) affecting the Simple Share WordPress plugin up to version 0.5.3. The vulnerability arises because the plugin fails to properly sanitize and escape certain settings inputs. This flaw allows users with high privileges, such as administrators, to inject and store malicious scripts (Stored XSS) within the plugin's settings. Notably, this can occur even when the WordPress capability 'unfiltered_html' is disabled, such as in multisite environments, which normally restricts the ability to post unfiltered HTML content. The attack vector requires the attacker to have high privileges (admin level) and some user interaction (e.g., visiting a page where the malicious script executes). The vulnerability impacts confidentiality and integrity by enabling script execution in the context of the victim's browser, potentially leading to session hijacking, privilege escalation, or further attacks on site users or administrators. The CVSS 3.1 base score is 4.8 (medium), reflecting network attack vector, low attack complexity, high privileges required, user interaction required, and partial impact on confidentiality and integrity but no impact on availability. There are no known exploits in the wild at the time of publication, and no official patches have been linked yet. The vulnerability is relevant primarily to WordPress sites using the Simple Share plugin, which is a niche product but could be targeted in environments where administrators have insufficient input validation controls. The scope is limited to sites where the plugin is installed and configured, and the attacker has admin access to inject malicious payloads.

For European organizations, this vulnerability poses a moderate risk primarily to websites running WordPress with the Simple Share plugin installed. Successful exploitation could allow attackers with admin privileges to execute malicious scripts in the context of other administrators or users, potentially leading to credential theft, session hijacking, or unauthorized actions within the WordPress admin interface. This could compromise the integrity of the website content and administrative controls, leading to reputational damage and potential data breaches. Given that many European organizations rely on WordPress for their web presence, especially small to medium enterprises and public sector entities, the impact could be significant if the plugin is widely used. However, the requirement for high privilege access limits the risk to insider threats or attackers who have already compromised admin credentials. The vulnerability could also affect multisite WordPress installations common in larger organizations, where disabling unfiltered_html is a common security measure, thus bypassing this protection. The lack of known exploits reduces immediate risk but does not eliminate the need for vigilance.

European organizations should immediately audit their WordPress installations to identify the presence of the Simple Share plugin, particularly versions up to 0.5.3. If found, they should consider disabling or removing the plugin until an official patch is released. Administrators must enforce strict access controls to limit the number of users with high privileges and monitor admin accounts for suspicious activity. Implementing Web Application Firewalls (WAFs) with custom rules to detect and block suspicious input patterns related to XSS payloads in plugin settings can provide additional protection. Organizations should also ensure that all user inputs, especially those from admin users, are sanitized and escaped properly at the application level, possibly by applying custom filters or security plugins that enforce input validation. Regular backups and monitoring of WordPress logs for unusual changes in plugin settings can help detect exploitation attempts early. Finally, organizations should subscribe to vulnerability disclosure feeds and update the plugin promptly once a patch becomes available.