CVE-2025-59545: 
C# vulnerability analysis and mitigation

DNN (formerly DotNetNuke), an open-source web content management platform in the Microsoft ecosystem powering over 750,000 websites globally, was found to contain a critical stored cross-site scripting (XSS) vulnerability tracked as CVE-2025-59545. The vulnerability was discovered in versions prior to 10.1.0 of the platform's Prompt module, which was disclosed on September 23, 2025 (NVD, Security Online).

The vulnerability lies in the Prompt module's command execution functionality that can return raw HTML. While DNN sanitizes most user-submitted data for safe display, the Prompt module processes malicious input in ways that bypass these defenses. The flaw has received a CVSS v3.1 base score of 9.0 (Critical) with the vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H, indicating network attack vector, low attack complexity, low privileges required, and high impact on confidentiality, integrity, and availability (GitHub Advisory).

The vulnerability could allow attackers to hijack administrator sessions, steal sensitive data, or alter site configurations. This is particularly dangerous for enterprise, government, and commercial portals built on DNN. With more than 8 million downloads and a community of 1 million members, the potential impact is significant, especially when executed in the context of a super-user (Security Online).

DNN has released version 10.1.0 to patch this vulnerability. Organizations are strongly urged to update immediately. For those unable to upgrade immediately, it is recommended to restrict access to the Prompt module and monitor administrative activity logs for signs of suspicious command execution (Security Online).