CVE-2025-32035 in Dnn.Platform
Summary
by MITRE • 04/08/2025
DNN (formerly DotNetNuke) is an open-source web content management platform (CMS) in the Microsoft ecosystem. Prior to 9.13.2, when uploading files (e.g. when uploading assets), the file extension is checked to see if it's an allowed file type but the actual contents of the file aren't checked. This means that it's possible to e.g. upload an executable file renamed to be a .jpg. This file could then be executed by another security vulnerability. This vulnerability is fixed in 9.13.2.
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Analysis
by VulDB Data Team • 08/26/2025
The vulnerability identified as CVE-2025-32035 affects DNN (formerly DotNetNuke) content management systems prior to version 9.13.2, representing a critical security flaw in the file upload validation mechanism. This issue stems from an incomplete validation approach that only examines file extensions rather than examining the actual file contents, creating a significant attack surface for malicious actors. The vulnerability resides in the core file handling functionality of the platform, which is widely used within the Microsoft ecosystem for web content management and enterprise applications.
The technical flaw manifests as a lack of comprehensive file type verification within the upload process, specifically failing to implement magic number or content-based validation. This allows attackers to bypass the extension-based whitelist validation by renaming malicious files with permitted extensions such as .jpg, .png, or .gif, while maintaining their executable or malicious content. The vulnerability is classified under CWE-502, which addresses "Deserialization of Untrusted Data," as it enables the execution of arbitrary code through improperly validated file uploads. This weakness directly enables a path for remote code execution attacks and represents a classic example of insufficient input validation in web applications.
The operational impact of this vulnerability extends beyond simple file upload capabilities, as it creates multiple potential attack vectors within the DNN platform. Attackers can leverage this flaw to upload malicious executables, web shells, or other harmful payloads that can be executed through secondary vulnerabilities or by exploiting the platform's file handling mechanisms. The vulnerability is particularly dangerous because it can be exploited by unauthenticated users, making it accessible to anyone with access to the upload functionality. This creates a persistent threat that can lead to full system compromise, data exfiltration, and lateral movement within network environments where DNN platforms are deployed.
Organizations using DNN versions prior to 9.13.2 should immediately implement mitigations including the mandatory upgrade to version 9.13.2 or later, which addresses the vulnerability through enhanced file validation mechanisms. Additional protective measures include implementing strict file type validation at multiple layers, including server-side content verification, implementing web application firewalls with file inspection capabilities, and establishing comprehensive monitoring for suspicious upload activities. The ATT&CK framework categorizes this vulnerability under T1190 "Exploit Public-Facing Application" and T1059 "Command and Scripting Interpreter," highlighting the potential for attackers to establish persistence and execute malicious commands through the compromised upload functionality. Security teams should also consider implementing principle of least privilege access controls for upload features and conducting regular security assessments to identify similar validation weaknesses in other applications.