CVE-2025-62802 is a vulnerability identified in the Dnn.Platform, an open-source web content management system widely used within the Microsoft ecosystem. The issue stems from an insecure default initialization of the HTML editor component prior to version 10.1.1, which allows unauthenticated users to upload files to the server. This behavior violates the principle of least privilege and introduces a significant attack vector. The vulnerability is categorized under CWE-1188 (Insecure Default Initialization of Resource) and CWE-434 (Unrestricted Upload of File with Dangerous Type). Because the platform permits file uploads without requiring authentication, attackers can potentially upload malicious files, leading to further exploitation such as code execution, website defacement, or pivoting within the network. The CVSS v3.1 base score is 4.3, reflecting a medium severity level, with an attack vector of network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), and requiring user interaction (UI:R). The impact primarily affects integrity, with no direct confidentiality or availability impact reported. No known exploits have been observed in the wild yet, but the vulnerability's nature and ease of exploitation make it a notable risk. The vendor has addressed the issue in Dnn.Platform version 10.1.1, and users are strongly advised to upgrade. The vulnerability is particularly relevant for organizations that deploy Dnn.Platform in public-facing environments without additional hardening or access controls.

For European organizations, this vulnerability poses a risk of unauthorized file uploads by unauthenticated attackers, potentially leading to website defacement, injection of malicious scripts, or further exploitation such as remote code execution if combined with other vulnerabilities. This can damage organizational reputation, disrupt services, and lead to data integrity issues. Public sector entities, educational institutions, and businesses relying on Dnn.Platform for their web presence are at risk, especially if they have not applied the patch or disabled the vulnerable feature. The impact is heightened in sectors where web integrity is critical, such as government portals or e-commerce platforms. Although the vulnerability does not directly compromise confidentiality or availability, the integrity compromise can indirectly lead to data breaches or service disruptions. The lack of authentication requirement and network accessibility make exploitation feasible by remote attackers, increasing the threat surface. Given the medium CVSS score, the threat should be prioritized in patch management cycles, particularly for organizations with high exposure to web-based attacks.

1. Upgrade all Dnn.Platform instances to version 10.1.1 or later immediately to eliminate the vulnerability. 2. If immediate upgrade is not feasible, disable the HTML editor's unauthenticated file upload feature via configuration settings or access control mechanisms. 3. Implement strict web application firewall (WAF) rules to detect and block unauthorized file upload attempts targeting the HTML editor endpoints. 4. Conduct regular audits of web server file directories to identify and remove any unauthorized or suspicious files. 5. Monitor web server and application logs for unusual upload activity or repeated access attempts to the HTML editor upload functionality. 6. Enforce least privilege principles by restricting file upload permissions to authenticated and authorized users only. 7. Educate web administrators and developers about secure configuration practices for Dnn.Platform and the risks of default insecure settings. 8. Employ network segmentation and intrusion detection systems to limit potential lateral movement if exploitation occurs. 9. Review and tighten overall CMS security posture, including patch management, user access controls, and secure coding practices.