CVE-2025-58025 is a stored Cross-Site Scripting (XSS) vulnerability classified under CWE-79, affecting the averta Master Slider plugin up to version 3.11.0. The vulnerability arises from improper neutralization of input during web page generation, allowing malicious actors to inject and persistently store malicious scripts within the application. When a user accesses the affected page, the malicious script executes in the context of the victim's browser, potentially leading to session hijacking, credential theft, defacement, or further exploitation of the victim's environment. The vulnerability requires low attack complexity (AC:L) and only low privileges (PR:L), meaning an authenticated user with limited permissions can exploit it. User interaction (UI:R) is required, as the victim must load the malicious content. The scope is changed (S:C), indicating that the vulnerability can affect resources beyond the vulnerable component, impacting confidentiality, integrity, and availability to a limited extent (C:L, I:L, A:L). No known exploits are currently reported in the wild, but the medium CVSS score of 6.5 reflects a moderate risk. The absence of a patch link suggests that a fix may not yet be publicly available, increasing the urgency for mitigation. Master Slider is a widely used WordPress plugin for creating responsive sliders, commonly deployed on websites for marketing and content presentation purposes. Stored XSS in such a plugin can be particularly dangerous as it can affect all visitors to a compromised site, including administrators and end-users.

For European organizations, this vulnerability poses a significant risk, especially for those relying on WordPress websites with the Master Slider plugin installed. Exploitation could lead to unauthorized access to user sessions, theft of sensitive data, and potential defacement or disruption of web services. This can damage brand reputation, lead to regulatory non-compliance under GDPR due to data breaches, and cause financial losses. Organizations in sectors such as e-commerce, media, education, and government, which often use WordPress for public-facing sites, are particularly vulnerable. The ability of an attacker with low privileges to inject persistent scripts means insider threats or compromised user accounts could be leveraged to escalate attacks. Additionally, the cross-site scripting could be used as a pivot point for further attacks within the network or to distribute malware to site visitors.

Immediate mitigation steps include restricting user input capabilities to trusted users only and implementing strict input validation and output encoding on all data rendered by the Master Slider plugin. Organizations should monitor and audit user-generated content for suspicious scripts. Until an official patch is released, consider disabling or removing the Master Slider plugin if feasible. Employ Web Application Firewalls (WAFs) with rules to detect and block XSS payloads targeting the plugin. Regularly update WordPress core and all plugins to the latest versions. Additionally, enforce the principle of least privilege for user accounts to limit the ability of low-privilege users to inject malicious content. Conduct security awareness training for administrators and content editors to recognize and report suspicious activity. Finally, implement Content Security Policy (CSP) headers to reduce the impact of potential XSS attacks by restricting script execution sources.