CVE-2025-13977 is a stored Cross-Site Scripting (XSS) vulnerability identified in the Essential Addons for Elementor – Popular Elementor Templates & Widgets plugin for WordPress, affecting all versions up to and including 6.5.3. The vulnerability stems from insufficient input sanitization and output escaping in two specific components: the Event Calendar widget's handling of custom attributes and the Image Masking module's rendering of element IDs. Authenticated attackers with Contributor-level permissions or higher can exploit this flaw by injecting arbitrary JavaScript code into pages through these vectors. Because the malicious scripts are stored persistently in the website’s content, they execute automatically whenever any user accesses the infected page, potentially compromising user sessions, stealing cookies, or performing unauthorized actions on behalf of users. The vulnerability has a CVSS 3.1 base score of 6.4, reflecting medium severity, with an attack vector of network, low attack complexity, requiring privileges (Contributor or above), no user interaction, and a scope change indicating that the vulnerability affects resources beyond the initially vulnerable component. No public exploits have been reported yet, but the presence of this vulnerability in a widely used WordPress plugin poses a significant risk. The plugin’s popularity among WordPress users means many websites could be vulnerable, especially those allowing multiple contributors to publish content. The vulnerability highlights the importance of proper input validation and output encoding in web applications to prevent injection attacks. Since no patch links are currently available, users must monitor vendor updates closely or implement temporary mitigations.

For European organizations, this vulnerability can lead to unauthorized script execution on their WordPress-powered websites, potentially resulting in session hijacking, defacement, phishing, or unauthorized actions performed in the context of legitimate users. This can damage brand reputation, lead to data breaches involving user credentials or personal data, and disrupt business operations. Organizations with multi-user content management workflows are particularly at risk because the exploit requires Contributor-level access or higher, which is common in collaborative environments. The vulnerability could also be leveraged as a foothold for further attacks within the network if attackers gain persistent access. Given the widespread use of WordPress and the Essential Addons plugin in Europe, especially among SMEs and content-heavy sites, the impact could be broad. Additionally, regulatory frameworks such as GDPR impose strict requirements on data protection, and exploitation of this vulnerability could lead to compliance violations and financial penalties if personal data is compromised.

European organizations should take immediate steps to mitigate this vulnerability. First, they should monitor the plugin vendor’s official channels for security patches and apply updates as soon as they become available. Until a patch is released, administrators should restrict Contributor-level permissions to trusted users only and review existing contributors for suspicious accounts. Implementing Web Application Firewalls (WAFs) with rules targeting common XSS payloads can provide temporary protection. Additionally, organizations can audit and sanitize existing content in the Event Calendar and Image Masking modules to remove potentially malicious scripts. Employing Content Security Policy (CSP) headers can help mitigate the impact of injected scripts by restricting script execution sources. Regular security training for content contributors to recognize and avoid unsafe input practices is also recommended. Finally, organizations should conduct thorough security assessments of their WordPress environments to identify and remediate similar vulnerabilities proactively.