CVE-2025-4963 is a stored Cross-Site Scripting (XSS) vulnerability identified in the WP Extended plugin for WordPress, known as The Ultimate WordPress Toolkit – WP Extended. This vulnerability affects all versions up to and including 3.0.15. The root cause is insufficient input sanitization and output escaping of SVG file uploads. Authenticated attackers with Author-level privileges or higher can exploit this flaw by uploading malicious SVG files containing embedded JavaScript code. When any user accesses a page that loads the malicious SVG, the injected script executes in their browser context. This can lead to session hijacking, defacement, or further exploitation such as privilege escalation or lateral movement within the WordPress environment. The vulnerability is classified under CWE-79, which relates to improper neutralization of input during web page generation. The CVSS v3.1 base score is 6.4 (medium severity), reflecting that the attack vector is network-based, requires low complexity, privileges at the Author level, no user interaction, and impacts confidentiality and integrity with a scope change (potentially affecting other components). No known exploits are currently reported in the wild, and no patches have been published yet. The vulnerability is significant because SVG files are commonly used for scalable graphics on websites, and WordPress is a widely deployed CMS platform, making this a notable risk for many websites using this plugin.

For European organizations, this vulnerability poses a moderate risk primarily to websites and web applications running WordPress with the WP Extended plugin installed. Exploitation could lead to unauthorized script execution in users' browsers, potentially compromising user sessions, stealing sensitive information, or defacing websites. This can damage organizational reputation, lead to data breaches, and disrupt business operations, especially for e-commerce, government portals, and media sites relying on WordPress. Since the attack requires authenticated Author-level access, the threat is more relevant in environments where multiple users have content publishing rights or where credential compromise is possible. The scope change in the CVSS vector indicates that the impact could extend beyond the immediate WordPress site, potentially affecting integrated systems or services. Given the widespread use of WordPress across Europe, the vulnerability could affect a broad range of sectors including public administration, education, and private enterprises. However, the absence of known exploits in the wild and the medium severity rating suggest that immediate catastrophic impact is unlikely but should not be ignored.

European organizations should take the following specific actions beyond generic patching advice: 1) Immediately audit WordPress installations to identify the presence and version of the WP Extended plugin. 2) Restrict Author-level privileges strictly to trusted users and review user roles to minimize unnecessary elevated access. 3) Implement strict file upload controls and scanning, especially for SVG files, using security plugins or web application firewalls (WAF) that can detect and block malicious SVG payloads. 4) Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts in browsers. 5) Monitor web server and application logs for unusual SVG upload activity or script execution patterns. 6) Prepare incident response plans for potential exploitation scenarios involving XSS. 7) Stay alert for official patches or updates from the WP Extended plugin vendor and apply them promptly once available. 8) Consider disabling SVG uploads temporarily if feasible until a patch is released. These measures collectively reduce the attack surface and mitigate the risk of exploitation.