CVE-2022-4750 is a medium-severity Stored Cross-Site Scripting (XSS) vulnerability affecting the WordPress plugin 'WP Responsive Testimonials Slider And Widget' up to version 1.5. The vulnerability arises because the plugin fails to properly validate and escape certain shortcode attributes before rendering them on pages or posts where the shortcode is embedded. This improper handling allows users with contributor-level permissions or higher to inject malicious scripts that get stored and executed in the context of other users viewing the affected content. Specifically, the vulnerability is classified under CWE-79, which pertains to improper neutralization of input during web page generation, leading to XSS. The CVSS 3.1 score is 5.4 (medium), with the vector indicating network attack vector (AV:N), low attack complexity (AC:L), requiring privileges (PR:L), user interaction (UI:R), scope changed (S:C), and impacts on confidentiality and integrity but not availability (C:L/I:L/A:N). No public exploits are currently known in the wild, and no patches have been linked, indicating that mitigation may rely on plugin updates or manual code fixes. The vulnerability allows an attacker with contributor or higher privileges to embed malicious JavaScript in shortcode attributes, which then executes in the browsers of users who view the affected pages, potentially leading to session hijacking, privilege escalation, or data theft within the WordPress environment. The scope change in the CVSS vector suggests that the vulnerability can affect resources beyond the initially vulnerable component, possibly impacting the entire WordPress site or user sessions.

For European organizations using WordPress sites with the 'WP Responsive Testimonials Slider And Widget' plugin, this vulnerability poses a moderate risk. Since exploitation requires contributor-level access, attackers would need to have some level of authenticated access, which might be achievable through social engineering, credential compromise, or insider threats. Once exploited, the stored XSS can lead to theft of session cookies, enabling privilege escalation to administrator roles, defacement of websites, or distribution of malware to site visitors. This can damage organizational reputation, lead to data breaches involving personal data protected under GDPR, and cause operational disruptions. Given the widespread use of WordPress across European businesses, including SMEs and public sector entities, the vulnerability could be leveraged to target organizations with less mature security controls. The scope change means that the impact could extend beyond the plugin itself, potentially compromising the entire site and its users. However, the lack of known exploits in the wild and the medium CVSS score indicate that the threat is currently moderate but should be addressed promptly to prevent escalation.

European organizations should first identify if their WordPress installations use the 'WP Responsive Testimonials Slider And Widget' plugin, especially versions up to 1.5. Since no official patch links are provided, organizations should monitor the plugin vendor’s official channels for updates or security patches. In the interim, restrict contributor-level permissions strictly to trusted users and audit existing contributor accounts for suspicious activity. Implement Web Application Firewall (WAF) rules to detect and block suspicious shortcode attribute inputs that may contain script tags or JavaScript event handlers. Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts on affected sites. Additionally, sanitize and validate all user inputs at the application level, possibly by customizing the plugin code to escape shortcode attributes properly if immediate patching is not available. Regularly review and update WordPress core, themes, and plugins to minimize exposure to known vulnerabilities. Conduct security awareness training to reduce the risk of credential compromise that could lead to unauthorized contributor access.