CVE-2025-50027 is a stored Cross-site Scripting (XSS) vulnerability classified under CWE-79, affecting the xootix Login/Signup Popup component up to version 2.9.4. This vulnerability arises from improper neutralization of input during web page generation, allowing malicious scripts to be injected and persistently stored within the application. When a victim accesses the affected page, the malicious script executes in their browser context, potentially leading to session hijacking, credential theft, or unauthorized actions performed on behalf of the user. The vulnerability requires an attacker with some level of privileges (PR:H) and user interaction (UI:R) to exploit, but the attack vector is network accessible (AV:N) with low attack complexity (AC:L). The scope is changed (S:C), indicating that exploitation can affect resources beyond the vulnerable component. The CVSS v3.1 score is 5.9 (medium severity), reflecting limited confidentiality, integrity, and availability impacts (C:L/I:L/A:L). No known exploits are currently reported in the wild, and no patches are publicly available at the time of publication. The vulnerability is particularly relevant for web applications using the xootix Login/Signup Popup, which is a popular plugin for user authentication interfaces in content management systems and websites. Stored XSS vulnerabilities are dangerous because they can affect multiple users and persist until remediated, making them a significant risk for web platforms handling sensitive user data or authentication workflows.

For European organizations, this vulnerability poses a moderate risk primarily to web applications that utilize the xootix Login/Signup Popup for user authentication. Exploitation could lead to unauthorized access to user sessions, theft of personal data, and potential lateral movement within affected systems. Given the nature of stored XSS, attackers could target multiple users, including employees or customers, leading to reputational damage and regulatory compliance issues under GDPR due to potential personal data exposure. The integrity of user accounts and the availability of authentication services could be compromised, disrupting business operations. Organizations in sectors with high reliance on web-based user authentication—such as e-commerce, financial services, healthcare, and public administration—are particularly vulnerable. The medium CVSS score suggests that while the vulnerability is not critical, it still warrants timely remediation to prevent exploitation, especially in environments where attackers may have some level of authenticated access or where user interaction can be socially engineered.

1. Immediate mitigation should include implementing strict input validation and output encoding on all user-supplied data within the Login/Signup Popup to neutralize malicious scripts. 2. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of potential XSS payloads. 3. Monitor and audit user inputs and stored content for suspicious or anomalous entries that could indicate exploitation attempts. 4. Limit privileges of users who can submit data to the vulnerable component to reduce the risk of exploitation by authenticated attackers. 5. Educate users and administrators about phishing and social engineering tactics that could facilitate user interaction required for exploitation. 6. Stay updated with vendor advisories and apply patches promptly once available. 7. Consider deploying Web Application Firewalls (WAFs) with custom rules targeting known XSS attack patterns specific to the xootix Login/Signup Popup. 8. Conduct regular security assessments and penetration testing focusing on authentication components to detect similar vulnerabilities proactively.