CVE-2025-13989 is a stored Cross-Site Scripting (XSS) vulnerability identified in the WP Dropzone plugin for WordPress, maintained by nazsabuz. The flaw exists in all versions up to and including 1.1.1 and stems from improper neutralization of user input in the 'callback' shortcode attribute. Specifically, the plugin evaluates this attribute as JavaScript code using the new Function() constructor without adequate input sanitization or output escaping. This allows authenticated attackers with Contributor-level access or higher to inject arbitrary JavaScript payloads into pages. These malicious scripts are stored persistently and execute in the context of any user who visits the affected page, potentially leading to session hijacking, privilege escalation, or data theft. The vulnerability is exploitable remotely over the network, requires low attack complexity, and does not need user interaction, but does require authenticated access with contributor or higher privileges. The CVSS 3.1 base score is 6.4, reflecting medium severity with partial impact on confidentiality and integrity but no impact on availability. No public exploits have been reported yet, but the vulnerability's nature makes it a significant risk for WordPress sites using this plugin, especially those with multiple contributors or editors. The vulnerability was published on December 12, 2025, and is tracked under CWE-79 (Improper Neutralization of Input During Web Page Generation).

For European organizations, this vulnerability poses a moderate risk primarily to the confidentiality and integrity of their WordPress-based web content. Attackers with contributor-level access can inject malicious scripts that execute in the browsers of site visitors or administrators, potentially leading to session hijacking, theft of sensitive information, or unauthorized actions performed on behalf of users. This can damage organizational reputation, lead to data breaches, or facilitate further attacks such as phishing or malware distribution. Given the widespread use of WordPress across Europe, especially among SMEs and content-driven organizations, the vulnerability could affect a broad range of sectors including media, education, and e-commerce. The stored nature of the XSS means that once exploited, the malicious payload persists and can impact all users accessing the compromised pages. Although exploitation requires authenticated access, many WordPress sites allow contributor or editor roles to multiple users, increasing the attack surface. The lack of known exploits in the wild currently reduces immediate risk but does not eliminate the potential for future attacks. Organizations failing to address this vulnerability may face regulatory scrutiny under GDPR if personal data is compromised.

European organizations should take the following specific mitigation steps: 1) Immediately update the WP Dropzone plugin to a patched version once released by the vendor; if no patch is available, consider disabling or removing the plugin temporarily. 2) Restrict contributor-level access strictly to trusted users and review user roles and permissions regularly to minimize the number of users who can inject content. 3) Implement Web Application Firewall (WAF) rules to detect and block suspicious JavaScript code patterns, especially those involving the new Function() constructor in shortcode attributes. 4) Employ Content Security Policy (CSP) headers to restrict the execution of inline scripts and untrusted JavaScript sources. 5) Conduct regular security audits and code reviews of custom shortcodes or plugins that handle user input. 6) Educate content contributors about the risks of injecting untrusted code and enforce strict content validation policies. 7) Monitor logs and site behavior for unusual activity indicative of exploitation attempts. These measures go beyond generic advice by focusing on access control, proactive detection, and layered defenses tailored to the nature of this stored XSS vulnerability.