CVE-2025-3779 is a stored cross-site scripting vulnerability identified in the Personizely plugin for WordPress, which provides A/B testing, popups, website personalization, and related features. The vulnerability stems from improper neutralization of input during web page generation, specifically inadequate sanitization and escaping of the 'widgetId' parameter. Authenticated attackers with Contributor-level access or higher can exploit this flaw by injecting arbitrary JavaScript code into pages managed by the plugin. Because the malicious script is stored persistently, it executes in the context of any user who visits the affected page, potentially compromising user sessions, stealing cookies, or performing unauthorized actions on behalf of the user. The CVSS 3.1 base score is 6.4, reflecting a medium severity with network attack vector, low complexity, requiring privileges but no user interaction, and impacting confidentiality and integrity with no availability impact. The vulnerability affects all versions up to and including 0.10 of the plugin. Although no public exploits are currently known, the risk is significant due to the widespread use of WordPress and the plugin’s role in user-facing content. The vulnerability was reserved and published in April and May 2025 respectively, with enrichment from CISA. No official patches are listed yet, indicating that users must apply interim mitigations. The vulnerability is classified under CWE-79, highlighting the common risk of cross-site scripting in web applications.

The primary impact of CVE-2025-3779 is the compromise of confidentiality and integrity of user data on affected WordPress sites using the Personizely plugin. Successful exploitation allows attackers to execute arbitrary JavaScript in the context of users visiting the compromised pages, enabling session hijacking, credential theft, unauthorized actions, and potential malware distribution. This can lead to account takeover, defacement, or further compromise of the website and its users. Since the vulnerability requires Contributor-level access, attackers must first gain some level of authenticated access, which may be feasible through social engineering or exploiting other vulnerabilities. The scope includes all users who visit injected pages, potentially affecting large user bases. While availability is not directly impacted, reputational damage and loss of user trust can have significant business consequences. Organizations relying on Personizely for marketing or personalization risk exposure of sensitive customer data and disruption of marketing campaigns. The medium severity score reflects the balance between required privileges and the potential damage caused by exploitation.

To mitigate CVE-2025-3779, organizations should immediately restrict Contributor-level access to trusted users only, minimizing the risk of malicious script injection. Implement strict input validation and output encoding for the 'widgetId' parameter and any user-supplied data within the plugin’s configuration or content management interfaces. Monitor and audit user activities, especially those with elevated privileges, to detect suspicious behavior. Until an official patch is released, consider disabling or removing the Personizely plugin if feasible, or isolating it from critical user-facing pages. Employ web application firewalls (WAFs) with rules targeting common XSS payloads to provide an additional layer of defense. Educate content contributors about safe input practices and the risks of injecting untrusted content. Once a patch becomes available, apply it promptly and verify the remediation. Regularly update WordPress and all plugins to the latest versions to reduce exposure to known vulnerabilities. Additionally, implement Content Security Policy (CSP) headers to restrict script execution sources, mitigating the impact of potential XSS attacks.