CVE-2025-22550 identifies a stored Cross-site Scripting (XSS) vulnerability in the AddFunc Mobile Detect plugin by Joe Rhoney, affecting all versions up to and including 3.1. The vulnerability stems from improper neutralization of user-supplied input during the generation of web pages, allowing attackers to inject malicious JavaScript code that is persistently stored on the server. When other users access the affected pages, the malicious script executes in their browsers, potentially leading to session hijacking, credential theft, defacement, or distribution of malware. Stored XSS is particularly dangerous because the payload persists and can affect multiple users without requiring repeated attacker interaction. The plugin is commonly used to detect mobile devices and tailor web content accordingly, making it a component in many websites. No CVSS score has been assigned yet, and no public exploits have been reported, but the vulnerability is publicly disclosed and should be treated as a serious risk. The lack of input sanitization indicates a fundamental flaw in the plugin's handling of user data, which attackers can exploit remotely without authentication or user interaction beyond visiting a maliciously crafted page. This vulnerability highlights the importance of secure coding practices in web plugins that handle user input and generate dynamic content.

The stored XSS vulnerability in AddFunc Mobile Detect can have severe consequences for organizations worldwide. Attackers can exploit this flaw to execute arbitrary JavaScript in the context of affected websites, leading to theft of sensitive information such as cookies, session tokens, or personal data. This can result in account takeover, unauthorized actions on behalf of users, and erosion of user trust. Additionally, attackers may use the vulnerability to deliver malware or redirect users to malicious sites, impacting the availability and integrity of services. Since the vulnerability is stored, it can affect multiple users over time, amplifying its impact. Organizations relying on this plugin for mobile device detection risk reputational damage, regulatory penalties, and operational disruptions if exploited. The absence of authentication requirements and ease of exploitation increase the likelihood of attacks, especially on high-traffic websites. The vulnerability also poses risks to web administrators who may have elevated privileges, potentially leading to full site compromise if combined with other vulnerabilities.

To mitigate CVE-2025-22550, organizations should immediately audit their use of the AddFunc Mobile Detect plugin and upgrade to a patched version once available. In the absence of an official patch, apply the following mitigations: implement strict input validation and output encoding on all user-supplied data processed by the plugin; deploy a robust Content Security Policy (CSP) to restrict the execution of unauthorized scripts; sanitize stored data to remove any malicious payloads; restrict permissions for users who can submit content that the plugin processes; monitor web server logs and application behavior for signs of XSS exploitation attempts; consider temporarily disabling the plugin if it is not critical to operations; and educate developers and administrators about secure coding and plugin management practices. Additionally, use web application firewalls (WAFs) with rules targeting XSS payloads to provide an additional layer of defense. Regular security assessments and penetration testing should be conducted to detect any residual vulnerabilities.