CVE-2025-41049 is a stored Cross-Site Scripting (XSS) vulnerability identified in version 4.0.5 of the appRain CMF (Content Management Framework). The vulnerability arises due to improper neutralization of user input during web page generation, specifically involving the 'data[Addon][layouts]' and 'data[Addon][layouts_except]' parameters within the endpoint /apprain/developer/addons/update/appform. Because these parameters are not properly validated or sanitized, an authenticated attacker can inject malicious scripts that are stored on the server and subsequently executed in the browsers of users who access the affected pages. This stored XSS can lead to session hijacking, defacement, or redirection to malicious sites, compromising user confidentiality and integrity. The vulnerability requires low attack complexity and no privileges beyond authentication, with partial user interaction needed (e.g., victim visiting a crafted page). The CVSS v4.0 score is 5.1 (medium severity), reflecting network attack vector, low complexity, no privileges required beyond authentication, and limited scope impact. No known exploits are currently reported in the wild. The vulnerability is classified under CWE-79, highlighting improper input neutralization during web page generation. The lack of a patch link suggests that a fix may not yet be publicly available, emphasizing the need for immediate mitigation steps by affected organizations.

For European organizations using appRain CMF version 4.0.5, this vulnerability poses a moderate risk. Stored XSS can lead to unauthorized access to user sessions, data theft, and potential compromise of administrative accounts if attackers leverage the vulnerability to escalate privileges or conduct phishing attacks within trusted environments. Given that appRain CMF is a content management framework, exploitation could affect websites or internal portals, leading to reputational damage, regulatory non-compliance (e.g., GDPR breaches if personal data is exposed), and operational disruption. The requirement for authentication limits the attack surface to users with valid credentials, but insider threats or compromised accounts could be leveraged. The medium severity score indicates that while the impact is not critical, the vulnerability should not be ignored, especially in sectors with sensitive data or high web presence such as finance, healthcare, and government institutions in Europe.

European organizations should immediately audit their use of appRain CMF to identify any instances of version 4.0.5. Until an official patch is released, the following specific mitigations are recommended: 1) Implement strict input validation and output encoding on the 'data[Addon][layouts]' and 'data[Addon][layouts_except]' parameters at the application level, ensuring that any user-supplied data is sanitized to remove or encode potentially malicious scripts. 2) Restrict access to the /apprain/developer/addons/update/appform endpoint to only highly trusted users and monitor access logs for suspicious activity. 3) Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts in browsers. 4) Conduct regular security awareness training for authenticated users to recognize phishing and social engineering attempts that could exploit this vulnerability. 5) Monitor for unusual user behavior or signs of session hijacking. 6) Prepare for rapid deployment of patches once available from the vendor. 7) Consider implementing Web Application Firewalls (WAF) with custom rules to detect and block XSS payloads targeting these parameters.