CVE-2025-41050 is a stored Cross-Site Scripting (XSS) vulnerability identified in version 4.0.5 of the appRain CMF (Content Management Framework). The vulnerability arises from improper neutralization of user input during web page generation, specifically within the parameters 'data[Addon][layouts]' and 'data[Addon][layouts_except]' in the endpoint /apprain/developer/addons/update/base_libs. This flaw allows an authenticated user with low privileges to inject malicious scripts that are stored and subsequently executed in the context of other users or administrators who access the affected functionality. The vulnerability is classified under CWE-79, which pertains to improper input validation leading to XSS attacks. According to the CVSS v4.0 vector, the attack vector is network-based (AV:N), with low attack complexity (AC:L), no privileges required (PR:L indicates low privileges), and requires user interaction (UI:P). The vulnerability does not affect confidentiality, integrity, or availability directly but can lead to session hijacking, credential theft, or unauthorized actions performed on behalf of users. No known exploits are currently reported in the wild, and no official patches have been linked yet. The vulnerability was published on September 4, 2025, and reserved in April 2025. The medium severity score of 5.1 reflects the moderate risk posed by this vulnerability, given the need for authentication and user interaction but ease of exploitation once these conditions are met.

For European organizations using appRain CMF version 4.0.5, this vulnerability poses a significant risk to the security of their web applications. Stored XSS can lead to session hijacking, defacement, or redirection to malicious sites, potentially compromising user data and trust. In sectors such as finance, healthcare, and government, where appRain CMF might be used for content management, the exploitation of this vulnerability could lead to unauthorized access to sensitive information or disruption of services. The requirement for authenticated access limits the attack surface but does not eliminate the risk, especially in environments with many users or weak internal controls. Additionally, the vulnerability could be leveraged as a foothold for further attacks within the network. The absence of known exploits in the wild currently reduces immediate risk but does not preclude future exploitation. European organizations must consider the regulatory implications, including GDPR, as exploitation could lead to data breaches and associated penalties.

1. Immediate mitigation should include restricting access to the affected endpoint (/apprain/developer/addons/update/base_libs) to trusted administrators only, using network segmentation and access control lists. 2. Implement strict input validation and output encoding on the parameters 'data[Addon][layouts]' and 'data[Addon][layouts_except]' to neutralize potentially malicious scripts. 3. Monitor logs for unusual activity related to these parameters, especially from authenticated users with low privileges. 4. Employ Content Security Policy (CSP) headers to reduce the impact of XSS by restricting the execution of unauthorized scripts. 5. Conduct a thorough review of user roles and permissions to minimize the number of users with access to vulnerable functionality. 6. Stay alert for official patches or updates from appRain and apply them promptly once available. 7. Educate users and administrators about the risks of XSS and safe usage practices. 8. Consider deploying Web Application Firewalls (WAFs) with rules tailored to detect and block exploitation attempts targeting these parameters.