CVE-2025-41058 is a medium-severity stored Cross-Site Scripting (XSS) vulnerability identified in appRain CMF version 4.0.5. The vulnerability arises from improper neutralization of user input during web page generation, specifically due to insufficient validation of the 'data[Addon][layouts]' and 'data[Addon][layouts_except]' parameters in the /apprain/developer/addons/update/row_manager endpoint. This flaw allows an authenticated user with limited privileges to inject malicious scripts that are persistently stored and executed in the context of other users or administrators accessing the affected functionality. The vulnerability is classified under CWE-79, which covers improper input sanitization leading to XSS attacks. According to the CVSS v4.0 vector, the attack vector is network-based (AV:N), requires low attack complexity (AC:L), no privileges (PR:L) but does require some user interaction (UI:P). The vulnerability does not affect confidentiality, integrity, or availability directly but can be leveraged to execute arbitrary JavaScript in victims’ browsers, potentially leading to session hijacking, credential theft, or further exploitation. No known exploits are currently in the wild, and no official patches have been released yet. The vulnerability was published on September 4, 2025, and assigned by INCIBE. Given the nature of stored XSS, the risk is elevated in environments where multiple users access the same administrative or user interfaces, especially in multi-tenant or collaborative deployments of appRain CMF.

For European organizations using appRain CMF 4.0.5, this vulnerability poses a risk primarily to the confidentiality and integrity of user sessions and data accessed via the web interface. Attackers exploiting this flaw could execute malicious scripts in the browsers of authenticated users, potentially leading to session hijacking, unauthorized actions performed on behalf of users, or the theft of sensitive information such as cookies or tokens. This could further facilitate lateral movement within the organization’s network or lead to privilege escalation if administrative users are targeted. The impact is particularly significant for organizations relying on appRain CMF for critical web content management, internal portals, or customer-facing applications. Given the authenticated nature of the exploit, insider threats or compromised low-privilege accounts could be leveraged to launch attacks. The lack of current patches increases the window of exposure. Additionally, the vulnerability could undermine trust in affected services and lead to regulatory compliance issues under GDPR if personal data is compromised through exploitation.

1. Immediate mitigation should include restricting access to the /apprain/developer/addons/update/row_manager endpoint to only highly trusted administrators and monitoring for unusual activity. 2. Implement strict input validation and output encoding on the affected parameters ('data[Addon][layouts]' and 'data[Addon][layouts_except]') to neutralize any injected scripts. 3. Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts in browsers. 4. Conduct thorough code review and security testing of all user input handling in appRain CMF, especially in developer and addon management modules. 5. Monitor logs for signs of exploitation attempts or anomalous user behavior. 6. Educate users about the risks of XSS and encourage the use of multi-factor authentication to reduce the impact of session hijacking. 7. Stay updated with vendor advisories for patches or official fixes and apply them promptly once available. 8. Consider deploying Web Application Firewalls (WAFs) with custom rules to detect and block malicious payloads targeting these parameters.