CVE-2026-24784 is a medium-severity 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 starting from 9.0.0 up to but not including 9.13.10, and from 10.0.0 up to but not including 10.2.0. It arises because the platform improperly neutralizes input during web page generation, specifically in module headers and footers editable by content editors. This improper sanitization allows a content editor to inject arbitrary JavaScript code that executes in the context of other users visiting the affected pages. The vulnerability requires the attacker to have authenticated access with elevated privileges (content editor role) but does not require any user interaction for the malicious script to execute once injected. The CVSS v3.1 score is 6.8, reflecting a network attack vector with low attack complexity, requiring privileges but no user interaction, and resulting in high confidentiality impact but no integrity or availability impact. The vulnerability is fixed in versions 9.13.10 and 10.2.0. Although no known exploits are reported in the wild, the flaw poses significant risks including session hijacking, credential theft, and unauthorized data access due to script execution in victim browsers. The vulnerability's scope is limited to installations using the affected versions and where content editors have the ability to modify module headers or footers.

For European organizations, this vulnerability could lead to unauthorized disclosure of sensitive information, including session tokens, personal data, or internal system details, through malicious scripts executed in users' browsers. This is particularly critical for public sector entities, educational institutions, and enterprises relying on Dnn.Platform for internal or external web portals. The confidentiality breach could facilitate further attacks such as privilege escalation or lateral movement within networks. Although the vulnerability does not directly affect system integrity or availability, the exploitation could undermine user trust and lead to compliance violations under GDPR due to data exposure. The requirement for authenticated content editor privileges limits the attack surface but insider threats or compromised editor accounts could be leveraged by attackers. The absence of known exploits in the wild suggests limited current exploitation but also highlights the importance of proactive patching to mitigate future risks.

European organizations should immediately verify their Dnn.Platform version and upgrade to 9.13.10 or 10.2.0 or later where the vulnerability is patched. Restrict content editor privileges strictly to trusted personnel and implement strong authentication mechanisms such as multi-factor authentication (MFA) to reduce the risk of account compromise. Conduct regular audits of module header and footer content to detect unauthorized script injections. Employ Content Security Policy (CSP) headers to restrict the execution of inline scripts and reduce the impact of potential XSS attacks. Monitor web application logs for unusual editing activities or script insertions. Educate content editors about the risks of injecting untrusted code and enforce secure coding practices. Additionally, consider deploying web application firewalls (WAFs) with rules tuned to detect and block XSS payloads targeting Dnn.Platform. Finally, maintain an incident response plan to quickly address any detected exploitation attempts.