CVE-2026-24833 is a cross-site scripting (XSS) vulnerability classified under CWE-79 affecting the Dnn.Platform, an open-source web content management system widely used in the Microsoft ecosystem. The vulnerability exists in versions prior to 9.13.10 and between 10.0.0 and 10.2.0, where a module can be installed with a richtext description field that improperly neutralizes input. This allows an attacker to inject malicious scripts that execute within the Persona Bar interface, a privileged administrative panel. The vulnerability requires an attacker to have high privileges (such as module installation rights) and involves user interaction to trigger the script execution. The impact includes full compromise of confidentiality, integrity, and availability of the CMS environment, as the injected scripts run with elevated privileges, potentially enabling session hijacking, data theft, or further system compromise. Although no known exploits are currently reported in the wild, the vulnerability's presence in widely deployed versions and the high impact necessitate urgent remediation. The issue is resolved in versions 9.13.10 and 10.2.0 by properly sanitizing the richtext input in module descriptions to prevent script injection. The CVSS v3.1 score of 7.7 reflects the network attack vector, high privileges required, user interaction, and complete impact on system security properties.

For European organizations, this vulnerability poses a significant risk especially to those using Dnn.Platform for public-facing websites or internal portals. Exploitation could lead to unauthorized access to sensitive data, defacement of websites, or disruption of services, impacting business operations and reputation. Public sector entities, educational institutions, and enterprises relying on Dnn for content management are particularly vulnerable. The elevated privileges required limit exploitation to insiders or compromised accounts, but the potential for lateral movement and privilege escalation remains high. Given the integration of Dnn within Microsoft environments, the vulnerability could be leveraged as a foothold for broader network compromise. The lack of known exploits reduces immediate risk but does not eliminate the threat, especially as proof-of-concept code could emerge. Regulatory compliance in Europe, such as GDPR, may be impacted if personal data is exposed or integrity is compromised, leading to legal and financial consequences.

European organizations should immediately upgrade affected Dnn.Platform instances to versions 9.13.10 or 10.2.0 or later where the vulnerability is patched. Until patching is complete, restrict module installation privileges to the minimum necessary and monitor for suspicious activity in the Persona Bar. Implement strict input validation and sanitization policies for any custom modules or extensions. Conduct regular security audits and penetration testing focusing on CMS components. Employ web application firewalls (WAFs) with rules to detect and block XSS payloads targeting the Persona Bar interface. Educate administrators about the risks of installing untrusted modules and the importance of applying security updates promptly. Maintain comprehensive logging and alerting to detect potential exploitation attempts. Consider isolating the CMS environment from critical internal networks to limit lateral movement if compromise occurs.