CVE-2025-49442 is a stored Cross-site Scripting (XSS) vulnerability classified under CWE-79, affecting the Simple Nested Menu plugin developed by Mostafa Shahiri. This vulnerability arises from improper neutralization of input during web page generation, allowing malicious scripts to be injected and stored within the application. When a victim accesses a page containing the injected payload, the malicious script executes in their browser context. The vulnerability is present in versions up to 1.0 of Simple Nested Menu, though exact affected versions are unspecified. The CVSS v3.1 base score is 6.5 (medium severity), with vector AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L, indicating network attack vector, low attack complexity, requiring low privileges and user interaction, with a scope change and partial impact on confidentiality, integrity, and availability. Stored XSS can lead to session hijacking, credential theft, defacement, or further exploitation of the victim's browser or network. No known exploits are currently reported in the wild, and no patches or fixes have been linked yet. The vulnerability requires an authenticated user with low privileges to inject the malicious payload, which then affects other users who view the compromised content, expanding the impact scope.

For European organizations, this vulnerability poses a moderate risk, especially for those using the Simple Nested Menu plugin on their websites or internal portals. Stored XSS can compromise user accounts, steal sensitive data, and facilitate lateral movement within networks if administrative users are targeted. The scope change in the CVSS vector indicates that the vulnerability can affect resources beyond the initially compromised component, potentially impacting broader systems. Organizations in sectors with high web presence, such as e-commerce, government, education, and media, are particularly vulnerable to reputational damage and data breaches resulting from XSS attacks. Additionally, compliance with GDPR mandates protection of personal data, and exploitation of this vulnerability could lead to violations and subsequent penalties. The requirement for user interaction and low privileges to exploit means that internal users or customers could inadvertently trigger the attack, increasing the risk of widespread impact within an organization.

European organizations should first inventory their web assets to identify any use of the Simple Nested Menu plugin. Until an official patch is released, organizations should implement strict input validation and output encoding on all user-supplied data within the affected plugin or surrounding application layers. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts. Web Application Firewalls (WAFs) can be configured to detect and block typical XSS payloads targeting this vulnerability. Additionally, restrict user privileges to the minimum necessary to reduce the risk of malicious input submission. Regularly monitor web logs for suspicious activity indicative of attempted XSS exploitation. Educate users about the risks of interacting with untrusted content and encourage reporting of unusual website behavior. Once a patch becomes available, prioritize its deployment. If feasible, consider replacing the vulnerable plugin with a more secure alternative or custom-developed menu solutions that follow secure coding practices.