CVE-2025-67553 identifies a DOM-based Cross-site Scripting (XSS) vulnerability in the ThemeHigh Advanced FAQ Manager WordPress plugin, affecting versions up to and including 1.5.2. The vulnerability stems from improper neutralization of user-supplied input during the dynamic generation of web pages, specifically within the client-side DOM context. Unlike traditional reflected or stored XSS, DOM-based XSS occurs entirely on the client side, where malicious scripts are injected and executed by manipulating the DOM environment, often via URL parameters or other client-side inputs. This flaw allows attackers to craft malicious URLs or inputs that, when processed by the vulnerable plugin, execute arbitrary JavaScript in the context of the victim's browser. Potential consequences include session hijacking, credential theft, unauthorized actions on behalf of the user, and distribution of malware. The vulnerability does not require user authentication, increasing its risk profile. Although no public exploits have been reported yet, the widespread use of WordPress and the plugin's presence in many websites make this a significant threat. The lack of a CVSS score suggests the need for an independent severity assessment based on the vulnerability's characteristics. The vulnerability was published on December 9, 2025, and no official patches or mitigations have been linked yet, emphasizing the need for proactive defensive measures.

For European organizations, this vulnerability can lead to severe security breaches, especially for those relying on the Advanced FAQ Manager plugin on their WordPress sites. Exploitation could compromise user accounts, leak sensitive information, and enable attackers to perform unauthorized actions such as defacing websites or distributing malware. Public sector websites, e-commerce platforms, and corporate portals that use this plugin are at heightened risk due to their reliance on trust and data integrity. The impact extends to reputational damage, regulatory non-compliance (e.g., GDPR violations due to data breaches), and potential financial losses. Since the vulnerability is client-side and does not require authentication, it can be exploited by any attacker who can lure users to malicious URLs, increasing the attack surface. The absence of known exploits currently provides a window for mitigation, but the risk remains high given the ease of exploitation and potential for widespread impact across multiple sectors in Europe.

European organizations should immediately audit their WordPress installations to identify the presence of the ThemeHigh Advanced FAQ Manager plugin, especially versions up to 1.5.2. Until an official patch is released, organizations should implement strict Content Security Policies (CSP) to restrict the execution of unauthorized scripts and reduce the impact of DOM-based XSS. Input validation and output encoding should be enforced at the application level where possible, including sanitizing URL parameters and any user-controllable inputs processed by the plugin. Web Application Firewalls (WAFs) can be configured to detect and block suspicious payloads targeting this vulnerability. Organizations should also educate users about the risks of clicking on untrusted links and monitor web traffic for anomalous patterns. Once a patch is available, prompt updating of the plugin is critical. Additionally, security teams should conduct thorough penetration testing focusing on DOM-based XSS vectors to ensure no residual vulnerabilities remain.