CVE-2025-41047 is a 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 involving the 'data[Addon][layouts]' and 'data[Addon][layouts_except]' parameters in the endpoint /apprain/developer/addons/update/ace. 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 type of vulnerability falls under CWE-79, which is a common web application security weakness. The CVSS 4.0 base score is 5.1 (medium severity), reflecting that the attack vector is network-based, requires low attack complexity, no privileges, but does require some user interaction and low scope impact. The vulnerability does not compromise confidentiality, integrity, or availability directly but can be leveraged to execute arbitrary JavaScript in the context of the victim's browser, potentially leading to session hijacking, credential theft, or other malicious activities. 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 by INCIBE, indicating recent discovery and disclosure. The affected product, appRain CMF, is a content management framework used to build and manage web applications, which may be deployed in various organizational contexts.

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 affected web application. An attacker with authenticated access can inject malicious scripts that execute in the browsers of other users, potentially leading to session hijacking, unauthorized actions, or data theft. This can undermine trust in the affected service and lead to reputational damage, especially if sensitive or personal data is exposed. Given the medium CVSS score and requirement for authentication and user interaction, the risk is moderate but should not be underestimated, particularly for organizations handling sensitive information or operating in regulated sectors such as finance, healthcare, or government. Additionally, exploitation could be a stepping stone for further attacks within the network. The lack of known exploits in the wild suggests limited immediate threat, but the vulnerability's presence in a web-facing application means it could be targeted once exploit code becomes available.

Organizations should prioritize upgrading or patching appRain CMF to a version where this vulnerability is fixed once available. In the absence of an official patch, immediate mitigations include implementing strict input validation and output encoding on the affected parameters ('data[Addon][layouts]' and 'data[Addon][layouts_except]') to neutralize malicious scripts. Web Application Firewalls (WAFs) can be configured to detect and block suspicious payloads targeting these parameters. Additionally, enforcing the principle of least privilege for authenticated users can limit the potential for exploitation. Regular security audits and code reviews should be conducted to identify and remediate similar input validation issues. Organizations should also educate users about the risks of interacting with untrusted content and monitor logs for unusual activity related to the affected endpoints. Finally, implementing Content Security Policy (CSP) headers can reduce the impact of XSS by restricting the execution of unauthorized scripts.