CVE-2025-41038 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 in the 'data[Group][name]' parameter within the /apprain/admin/managegroup/add/ endpoint. This flaw allows an authenticated user with at least low privileges to inject malicious scripts that are stored on the server and later executed in the browsers of users who access the affected pages. The vulnerability is classified under CWE-79, which pertains to improper input validation leading to XSS attacks. The CVSS v4.0 base score is 5.1 (medium severity), reflecting that the attack vector is network-based, requires low complexity, no privileges are required beyond authentication, and user interaction is necessary. The vulnerability does not impact confidentiality, integrity, or availability directly but can be leveraged to perform session hijacking, defacement, or redirect users to malicious sites. 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 for building web applications, which may be deployed in various organizational environments.

For European organizations using appRain CMF 4.0.5, this vulnerability poses a risk primarily to web application security and user trust. An attacker exploiting this stored XSS could execute arbitrary JavaScript in the context of the victim’s browser, potentially leading to session hijacking, unauthorized actions on behalf of users, or distribution of malware. This can result in data leakage, reputational damage, and regulatory non-compliance, especially under GDPR where user data protection is critical. Since the vulnerability requires authentication, the risk is somewhat mitigated by access controls; however, insider threats or compromised accounts could be leveraged to exploit it. Organizations with public-facing admin panels or intranets using this version are particularly at risk. The medium severity score suggests moderate impact, but the potential for chained attacks or exploitation in combination with other vulnerabilities could elevate the threat. The lack of current known exploits provides a window for proactive mitigation before widespread attacks occur.

1. Immediate mitigation should include restricting access to the /apprain/admin/managegroup/add/ endpoint to trusted administrators only, using network segmentation and strong authentication mechanisms such as multi-factor authentication (MFA). 2. Implement strict input validation and output encoding on the 'data[Group][name]' parameter to neutralize potentially malicious scripts. This can be done by applying context-aware encoding (e.g., HTML entity encoding) before rendering user input in web pages. 3. Monitor logs for unusual activity or attempts to inject scripts via this parameter. 4. If possible, upgrade to a patched version of appRain CMF once available. In the absence of an official patch, consider applying custom patches or web application firewall (WAF) rules to detect and block malicious payloads targeting this parameter. 5. Conduct security awareness training for administrators to recognize phishing or social engineering attempts that could lead to account compromise. 6. Regularly audit user privileges to ensure minimal necessary access is granted. 7. Employ Content Security Policy (CSP) headers to reduce the impact of XSS by restricting the execution of unauthorized scripts.