CVE-2025-41042 is a stored Cross-Site Scripting (XSS) vulnerability identified in appRain CMF version 4.0.5. This vulnerability arises from improper neutralization of user input during web page generation, specifically within the parameters 'data[Option][message]', 'data[Option][subject]', and 'data[Option][templatetype]' in the endpoint /apprain/information/manage/emailtemplate/add. Because these parameters are not properly validated or sanitized, an authenticated user can inject malicious scripts that are stored on the server and later executed in the browsers of users who view the affected pages. The vulnerability requires low privileges (authenticated user) and user interaction (viewing the malicious content) but does not require additional authentication or complex attack vectors. The CVSS 4.0 score is 5.1, indicating a medium severity level. The vulnerability impacts confidentiality, integrity, and availability to a limited extent, as it can be used to execute arbitrary scripts, potentially leading to session hijacking, defacement, or phishing attacks within the context of the appRain CMF application. No known exploits are currently reported in the wild, and no patches have been published yet. The vulnerability was reserved in April 2025 and published in September 2025, with INCIBE as the assigner.

For European organizations using appRain CMF 4.0.5, this vulnerability poses a moderate risk. Stored XSS can allow attackers to execute arbitrary JavaScript in the context of the victim's browser, potentially leading to session hijacking, unauthorized actions, or data theft within the application. Since the vulnerability requires authenticated access, the threat is primarily from insider threats or compromised user accounts. However, the impact can extend to broader organizational security if attackers leverage this to escalate privileges or move laterally. Organizations in sectors with sensitive data or regulatory requirements (e.g., finance, healthcare, government) may face compliance risks if exploited. Additionally, the lack of a patch increases exposure time. The vulnerability could undermine user trust and damage reputation if exploited to deliver phishing or malware payloads through the application interface.

1. Immediate mitigation should include restricting access to the vulnerable endpoint to trusted users only and monitoring for suspicious activity related to email template management. 2. Implement strict input validation and output encoding on the affected parameters ('data[Option][message]', 'data[Option][subject]', 'data[Option][templatetype]') to neutralize any malicious scripts. 3. Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts in browsers. 4. Conduct thorough code reviews and security testing (including automated scanning and manual penetration testing) on the appRain CMF application to identify and remediate similar input validation issues. 5. Educate users and administrators about the risks of XSS and encourage strong authentication practices to reduce the risk of account compromise. 6. Stay alert for official patches or updates from appRain and apply them promptly once available. 7. Consider deploying Web Application Firewalls (WAFs) with custom rules to detect and block malicious payloads targeting these parameters.