CVE-2025-41039 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 due to insufficient validation and sanitization of multiple configuration parameters submitted via the /apprain/admin/config/opts endpoint. These parameters include 'data[sconfig][admin_landing_page]', 'data[sconfig][currency]', 'data[sconfig][db_version]', 'data[sconfig][default_pagination]', 'data[sconfig][emailsetup_from_email]', 'data[sconfig][emailsetup_host]', 'data[sconfig][emailsetup_password]', 'data[sconfig][emailsetup_port]', 'data[sconfig][emailsetup_username]', 'data[sconfig][fileresource_id]', 'data[sconfig][large_image_height]', 'data[sconfig][large_image_width]', and 'data[sconfig][time_zone_padding]'. Because the vulnerability is stored and authenticated, an attacker with legitimate access to the admin configuration interface can inject malicious scripts that are then persistently stored and executed in the context of other users or administrators viewing affected pages. The CVSS 4.0 base score of 5.1 (medium severity) reflects that the attack vector is network-based, requires low attack complexity, no privileges beyond authenticated user access, and user interaction is required to trigger the malicious script execution. The vulnerability does not impact confidentiality, integrity, or availability directly but can lead to session hijacking, privilege escalation, or other attacks leveraging the XSS flaw. No known exploits are reported in the wild yet, and no patches have been linked, indicating that organizations using appRain CMF 4.0.5 should proactively assess and mitigate this issue. The root cause is a failure to properly sanitize or encode user-supplied input before rendering it in the admin interface, violating CWE-79 standards for input validation and output encoding.

For European organizations using appRain CMF 4.0.5, this vulnerability poses a moderate risk primarily to the confidentiality and integrity of administrative sessions and data. Successful exploitation could allow attackers with authenticated access to inject malicious scripts that execute in the browsers of other administrators or users, potentially leading to session hijacking, unauthorized actions, or theft of sensitive configuration data. This can undermine trust in the affected systems and lead to further compromise of internal networks. While the vulnerability requires authenticated access, many organizations have multiple administrators or users with configuration privileges, increasing the attack surface. The persistent nature of the XSS means that once injected, malicious code can affect multiple users over time. Given the administrative context, the impact could extend to critical configuration changes or data leakage. European organizations in sectors with stringent data protection regulations (e.g., GDPR) may face compliance risks if such vulnerabilities lead to data breaches. Additionally, the lack of available patches means organizations must rely on compensating controls until official fixes are released. The medium severity rating suggests that while the vulnerability is not immediately critical, it should be addressed promptly to prevent escalation or exploitation in targeted attacks.

1. Immediate mitigation should include restricting access to the /apprain/admin/config/opts endpoint strictly to trusted administrators and limiting the number of users with configuration privileges. 2. Implement Web Application Firewall (WAF) rules to detect and block suspicious input patterns targeting the vulnerable parameters, especially script tags or event handlers. 3. Conduct manual input validation and sanitization on the server side for all configuration parameters before storing or rendering them, applying strict encoding to neutralize HTML and JavaScript content. 4. Monitor logs for unusual activity or repeated attempts to inject scripts via the affected parameters. 5. Until an official patch is released, consider disabling or restricting the affected configuration options if feasible. 6. Educate administrators about the risks of XSS and encourage the use of secure browsers with script-blocking extensions during administrative sessions. 7. Plan and prioritize upgrading to a patched version of appRain CMF once available, or apply vendor-provided workarounds. 8. Perform regular security assessments and penetration testing focused on administrative interfaces to detect similar vulnerabilities proactively.