CVE-2022-4010 is a medium-severity vulnerability affecting the WordPress plugin 'Image Hover Effects' prior to version 5.5. The vulnerability is a Stored Cross-Site Scripting (XSS) flaw categorized under CWE-79. It arises because the plugin fails to properly sanitize and escape certain settings, allowing malicious scripts to be stored and executed in the context of the WordPress site. Notably, this vulnerability can be exploited by users with high privileges, such as administrators, even when the unfiltered_html capability is disabled, which is common in multisite WordPress setups. The attack requires user interaction (UI:R), specifically the victim must load a page where the malicious script is rendered. The vulnerability has a CVSS 3.1 base score of 4.8, indicating medium severity, with an attack vector of network (AV:N), low attack complexity (AC:L), and privileges required being high (PR:H). The scope is changed (S:C), meaning the vulnerability affects resources beyond the security scope of the vulnerable component. The impact on confidentiality and integrity is low (C:L, I:L), and there is no impact on availability (A:N). There are no known exploits in the wild, and no official patches have been linked in the provided information. The vulnerability primarily affects WordPress sites using the Image Hover Effects plugin before version 5.5, which is used to add visual hover effects to images on websites.

For European organizations, the impact of this vulnerability depends largely on the extent to which the Image Hover Effects plugin is deployed within their WordPress environments. Since the vulnerability requires high privilege user access to exploit, the risk is primarily internal or from compromised administrator accounts. Successful exploitation could allow attackers to inject malicious scripts that execute in the context of the site, potentially leading to session hijacking, defacement, or further privilege escalation. This can undermine the integrity and confidentiality of the affected websites and potentially impact user trust and data privacy compliance, especially under GDPR regulations. Multisite WordPress installations, common in larger organizations and agencies, are particularly at risk because the vulnerability bypasses the unfiltered_html capability restrictions. Although there is no direct availability impact, the reputational damage and potential data leakage could be significant. The lack of known exploits in the wild reduces immediate risk, but the presence of a publicly known vulnerability increases the likelihood of targeted attacks if not remediated.

1. Immediate upgrade of the Image Hover Effects plugin to version 5.5 or later, where this vulnerability is fixed, is the most effective mitigation. 2. If upgrading is not immediately possible, restrict administrative access strictly to trusted personnel and enforce strong authentication mechanisms such as multi-factor authentication (MFA) to reduce the risk of compromised admin accounts. 3. Implement Content Security Policy (CSP) headers to limit the execution of unauthorized scripts on the website. 4. Regularly audit WordPress user privileges to ensure that only necessary users have high-level permissions. 5. Monitor WordPress logs and plugin settings for unusual changes or suspicious activity that could indicate exploitation attempts. 6. For multisite WordPress setups, review and tighten network-wide security policies and consider disabling or limiting the use of vulnerable plugins until patched. 7. Employ web application firewalls (WAF) with rules targeting XSS attacks to provide an additional layer of defense. 8. Educate site administrators about the risks of stored XSS and safe plugin management practices.