CVE-2025-63075 identifies a DOM-based Cross-site Scripting (XSS) vulnerability in the muffingroup Betheme WordPress theme, affecting all versions up to and including 28.1.7. This vulnerability stems from improper neutralization of user-supplied input during the generation of web pages, allowing malicious scripts to be injected and executed within the victim's browser environment. Unlike reflected or stored XSS, DOM-based XSS exploits client-side code, manipulating the Document Object Model to execute unauthorized scripts without server-side input validation. The Betheme theme is widely used for WordPress websites, which increases the attack surface. Although no public exploits have been reported yet, the vulnerability poses a significant risk because attackers can craft malicious URLs or payloads that, when visited by users, execute arbitrary JavaScript. This can lead to session hijacking, theft of cookies or credentials, defacement, or redirecting users to phishing or malware sites. The lack of a CVSS score indicates that the vulnerability is newly published and awaiting further assessment. The vulnerability was reserved in late October 2025 and published in December 2025, indicating recent discovery. The absence of patches at the time of publication suggests that users should be vigilant and apply updates as soon as they become available. The vulnerability requires no authentication and can be triggered through user interaction with crafted content, making it relatively easy to exploit. Given the nature of WordPress themes and their integration with various plugins and customizations, the impact can vary but generally threatens confidentiality and integrity of user sessions and data.

For European organizations, the impact of CVE-2025-63075 can be substantial, particularly for those relying on Betheme for their public-facing websites. Exploitation could lead to unauthorized access to user sessions, enabling attackers to impersonate legitimate users or administrators. This can result in data breaches, defacement of corporate websites, loss of customer trust, and potential regulatory penalties under GDPR if personal data is compromised. E-commerce sites, financial services, and public sector websites using Betheme are especially vulnerable due to the sensitivity of their data and the critical nature of their services. Additionally, successful XSS attacks can serve as a foothold for further attacks, such as delivering malware or phishing campaigns targeting European users. The reputational damage and operational disruption caused by such attacks could be significant. Since WordPress powers a large portion of European websites, and Betheme is a popular premium theme, the scope of affected systems is broad. Organizations with limited cybersecurity resources or delayed patch management processes face higher risks. The vulnerability's ease of exploitation without authentication increases the likelihood of attacks, emphasizing the need for proactive defense measures.

1. Monitor official muffingroup and Betheme channels for security patches and apply updates immediately once available to remediate the vulnerability. 2. Implement strict Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of potential XSS attacks. 3. Employ web application firewalls (WAFs) with rules specifically designed to detect and block DOM-based XSS payloads targeting Betheme. 4. Conduct thorough input validation and sanitization on all user-supplied data within the theme and any customizations, focusing on client-side scripts that manipulate the DOM. 5. Educate website administrators and developers about the risks of DOM-based XSS and best practices for secure coding and theme customization. 6. Regularly audit and scan websites using Betheme with automated vulnerability scanners that can detect XSS vulnerabilities. 7. Limit user privileges and enforce strong authentication mechanisms to minimize the impact of compromised sessions. 8. Consider deploying browser security features such as HTTPOnly and Secure flags on cookies to protect session tokens from theft via XSS. 9. Maintain comprehensive logging and monitoring to detect suspicious activities indicative of exploitation attempts. 10. For organizations with high-risk profiles, consider isolating critical web applications or using content delivery networks (CDNs) with security features to add an additional layer of defense.