CVE-2025-12652 identifies a stored Cross-Site Scripting (XSS) vulnerability in the Ungapped Widgets plugin for WordPress, specifically in the handling of the 'prefillvalues' parameter within the ungapped-form shortcode. The root cause is insufficient sanitization and output escaping of user-supplied input, allowing authenticated users with contributor-level privileges or higher to inject arbitrary JavaScript code into pages. When other users access these pages, the malicious scripts execute in their browsers, potentially compromising session tokens, user credentials, or enabling further attacks such as privilege escalation or data theft. The vulnerability affects all versions up to and including version 1 of the plugin. The CVSS 3.1 base score is 6.4, reflecting a medium severity with network attack vector, low attack complexity, requiring privileges but no user interaction, and impacting confidentiality and integrity with a scope change. No public exploits or patches are currently available, increasing the risk window. The vulnerability is particularly concerning for WordPress sites that allow contributor-level users to add or modify content using shortcodes, as it enables persistent script injection. Detection requires monitoring shortcode parameters for suspicious input, and mitigation currently relies on access control and manual input validation. This vulnerability exemplifies the risks of improper input neutralization (CWE-79) in web applications, especially in widely used CMS plugins.

For European organizations, this vulnerability can lead to unauthorized disclosure of sensitive information, session hijacking, and potential privilege escalation within WordPress-managed websites. Organizations relying on the Ungapped Widgets plugin for customer-facing or internal portals risk reputational damage and data breaches if attackers exploit this flaw. Since the attack requires contributor-level access, insider threats or compromised contributor accounts pose a significant risk. The persistent nature of stored XSS means injected scripts remain active until removed, increasing exposure time. This can disrupt business operations, lead to regulatory non-compliance under GDPR due to data leakage, and facilitate further attacks such as phishing or malware distribution. The medium severity score indicates a moderate but tangible threat, especially for sectors with high web presence like e-commerce, media, and public services. The absence of patches and known exploits suggests a window of opportunity for attackers to develop exploits, emphasizing the need for proactive mitigation.

1. Immediately restrict contributor-level access to trusted users only and review existing contributor accounts for suspicious activity. 2. Implement strict input validation and sanitization on the 'prefillvalues' parameter at the application or web server level using web application firewalls (WAFs) with custom rules to detect and block malicious scripts. 3. Monitor WordPress shortcode usage logs for anomalous or unexpected input patterns indicative of injection attempts. 4. Disable or remove the Ungapped Widgets plugin if it is not essential to reduce attack surface until a security patch is released. 5. Educate content contributors about the risks of injecting untrusted content and enforce secure content creation policies. 6. Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts on affected sites. 7. Regularly back up website data and maintain an incident response plan to quickly remediate any detected compromise. 8. Stay updated with vendor advisories and apply patches promptly once available.