CVE-2025-62146 identifies a stored Cross-site Scripting (XSS) vulnerability in the MX Time Zone Clocks plugin developed by Maksym Marko, affecting all versions up to 5.1.1. The vulnerability stems from improper neutralization of user-supplied input during the generation of web pages, specifically failing to sanitize or encode input that is later rendered in the browser. This allows an attacker with low privileges (PR:L) to inject malicious scripts that are stored persistently and executed when other users view the affected pages, requiring user interaction (UI:R). The vulnerability impacts confidentiality, integrity, and availability to a limited extent (C:L/I:L/A:L) and has a CVSS v3.1 base score of 6.5, categorizing it as medium severity. Although no known exploits have been reported in the wild, the vulnerability poses a risk to websites using this plugin, potentially enabling session hijacking, defacement, or redirection to malicious sites. The vulnerability is particularly relevant for websites that display time zone clocks dynamically based on user input or configuration, where input is not properly sanitized. No official patches or fixes have been published yet, increasing the urgency for defensive measures. The vulnerability was reserved in October 2025 and published at the end of 2025, indicating recent discovery. The CWE-79 classification confirms the nature of the issue as improper input neutralization leading to XSS.

For European organizations, the impact of this vulnerability can be significant, especially for those relying on MX Time Zone Clocks in public-facing websites or intranet portals. Exploitation could allow attackers to execute arbitrary JavaScript in the context of users’ browsers, leading to session hijacking, theft of sensitive information, or unauthorized actions performed on behalf of users. This can damage organizational reputation, lead to data breaches, and disrupt services. Given the medium severity, the impact is moderate but can escalate if combined with other vulnerabilities or social engineering attacks. Organizations in sectors such as finance, healthcare, and government, which handle sensitive data and have strict compliance requirements, may face regulatory consequences if exploited. The lack of patches increases exposure time, and the requirement for user interaction means phishing or social engineering could facilitate exploitation. The vulnerability also poses risks to the integrity of web content and availability if attackers inject disruptive scripts.

Since no patches are currently available, European organizations should implement immediate compensating controls. These include deploying Web Application Firewalls (WAFs) with rules to detect and block XSS payloads targeting the MX Time Zone Clocks plugin. Input validation and output encoding should be enforced at the application level where possible, especially sanitizing any user-supplied data that the plugin processes. Organizations should audit their websites to identify usage of the affected plugin and consider disabling or removing it until a patch is released. User awareness training to recognize phishing attempts can reduce the risk of user interaction exploitation. Monitoring web logs for unusual script injections or anomalous behavior can help detect exploitation attempts early. Once a patch is available, prompt application is critical. Additionally, adopting Content Security Policy (CSP) headers can mitigate the impact of XSS by restricting script execution sources.