CVE-2025-3779 is a stored Cross-Site Scripting (XSS) vulnerability affecting the Personizely plugin for WordPress, specifically impacting all versions up to and including 0.10. The vulnerability arises from improper neutralization of input during web page generation, classified under CWE-79. The flaw exists in the handling of the 'widgetId' parameter, where insufficient input sanitization and output escaping allow an authenticated attacker with Contributor-level privileges or higher to inject arbitrary malicious scripts into pages. These scripts execute whenever any user accesses the compromised page, potentially leading to session hijacking, defacement, or redirection to malicious sites. The vulnerability has a CVSS 3.1 base score of 6.4, indicating a medium severity level. The attack vector is network-based with low attack complexity and requires privileges equivalent to Contributor role, but no user interaction is needed for exploitation. The scope is changed (S:C), meaning the vulnerability affects resources beyond the vulnerable component, and the impact affects confidentiality and integrity, but not availability. No known exploits are currently reported in the wild, and no patches have been linked yet. The vulnerability is significant because WordPress is widely used for website management, and Personizely is a popular plugin for A/B testing and personalization, making the attack surface considerable for websites using this plugin. The stored nature of the XSS means injected scripts persist and can affect multiple users over time, increasing the risk of widespread impact once exploited.

For European organizations, this vulnerability poses a risk primarily to websites using WordPress with the Personizely plugin installed. Exploitation could lead to unauthorized script execution in the context of the affected website, compromising user sessions, stealing sensitive data such as cookies or authentication tokens, and potentially enabling further attacks like phishing or malware distribution. This can damage brand reputation, lead to regulatory non-compliance (e.g., GDPR breaches due to data leakage), and cause financial losses. Since the vulnerability requires Contributor-level access, insider threats or compromised accounts could be leveraged by attackers. The persistent nature of stored XSS increases the risk of long-term exploitation. Organizations relying on Personizely for marketing or customer engagement in Europe should be particularly vigilant, as the impact extends to both customer trust and operational security. Additionally, the scope change indicates that the vulnerability could affect other components or users beyond the initial injection point, amplifying the potential damage.

1. Immediate mitigation involves restricting Contributor-level access strictly to trusted personnel and reviewing user roles to minimize privilege exposure. 2. Apply input validation and output encoding for the 'widgetId' parameter in the Personizely plugin code to ensure all inputs are sanitized and escaped properly before rendering. 3. Monitor and audit logs for unusual activities related to widgetId manipulations or unexpected script injections. 4. Implement Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts on affected web pages, reducing the impact of potential XSS payloads. 5. Regularly update the Personizely plugin once the vendor releases a patch addressing this vulnerability. 6. Conduct security awareness training for administrators and contributors about the risks of XSS and safe plugin management. 7. Employ Web Application Firewalls (WAF) with rules targeting XSS patterns to detect and block exploitation attempts. 8. Perform periodic security assessments and penetration testing focusing on plugin vulnerabilities and user privilege misuse.