CVE-2025-49243 is a Stored Cross-site Scripting (XSS) vulnerability classified under CWE-79, affecting the sevenspark ShiftNav – Responsive Mobile Menu plugin. This vulnerability arises due to improper neutralization of input during web page generation, allowing malicious actors to inject and store arbitrary scripts within the affected web application. When a victim accesses the compromised page, the malicious script executes in their browser context, potentially leading to session hijacking, credential theft, defacement, or further exploitation of the victim's environment. The vulnerability affects all versions of ShiftNav – Responsive Mobile Menu up to and including version 1.8. The CVSS v3.1 base score is 6.5, indicating a medium severity level. The vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L) shows that the attack can be performed remotely over the network with low attack complexity, requires low privileges, and user interaction is needed. The scope is changed, meaning the vulnerability affects components beyond the initially vulnerable component. The impact includes low confidentiality, integrity, and availability impacts, but the stored nature of the XSS increases the risk of persistent exploitation. No known exploits are currently reported in the wild, and no official patches have been released yet. Stored XSS vulnerabilities are particularly dangerous because they can affect multiple users and persist until remediated. The plugin is commonly used to provide responsive mobile navigation menus on WordPress sites, making it a popular target for attackers aiming to compromise websites and their visitors.

For European organizations, especially those running WordPress websites with the ShiftNav plugin, this vulnerability poses a significant risk. Exploitation could lead to unauthorized access to user sessions, theft of sensitive information, and potential defacement or malware injection on corporate or customer-facing websites. This can damage brand reputation, lead to regulatory non-compliance (e.g., GDPR breaches if personal data is compromised), and cause operational disruptions. The medium severity score reflects the need for timely remediation to prevent attackers from leveraging this vulnerability for broader attacks such as phishing or lateral movement within networks. Organizations in sectors like e-commerce, finance, healthcare, and government are particularly at risk due to the sensitive nature of their data and the high value of their web presence. Additionally, the requirement for low privileges and user interaction means that attackers could exploit this vulnerability through social engineering or compromised user accounts, increasing the attack surface.

1. Immediate mitigation should include disabling or removing the ShiftNav – Responsive Mobile Menu plugin until a security patch is released. 2. Monitor and audit web application logs for unusual input or script injection attempts. 3. Implement Web Application Firewall (WAF) rules to detect and block XSS payloads targeting the affected plugin's endpoints. 4. Enforce Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in browsers. 5. Educate users and administrators on the risks of phishing and social engineering that could facilitate exploitation. 6. Once a patch is available, promptly update the plugin to the fixed version. 7. Conduct a thorough security review of all input handling and output encoding practices in the web application to prevent similar vulnerabilities. 8. Use security scanners to detect stored XSS vulnerabilities regularly. 9. Limit user privileges to the minimum necessary to reduce the risk of exploitation requiring low privileges. 10. Backup website data regularly to enable quick restoration in case of compromise.