CVE-2020-37103 in DotNetNuke
Summary
by MITRE • 02/03/2026
DotNetNuke 9.5 contains a persistent cross-site scripting vulnerability that allows normal users to upload malicious XML files with executable scripts through journal tools. Attackers can upload XML files with XHTML namespace scripts to execute arbitrary JavaScript in users' browsers, potentially bypassing CSRF protections and performing more damaging attacks.
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Analysis
by VulDB Data Team • 02/10/2026
The vulnerability identified as CVE-2020-37103 affects DotNetNuke version 9.5 and represents a critical persistent cross-site scripting flaw that exploits the platform's journal tools functionality. This vulnerability stems from inadequate input validation and sanitization mechanisms within the file upload processing system, specifically when handling XML files through the journal module. The flaw allows authenticated users with normal privileges to bypass standard security restrictions and upload malicious XML content that contains executable JavaScript code. The vulnerability manifests when the system fails to properly validate the content type and structure of uploaded files, particularly those utilizing XHTML namespace declarations that can be interpreted by web browsers as executable scripts rather than mere markup.
The technical implementation of this vulnerability leverages the XML parsing behavior within DotNetNuke's journal tools, where the system accepts XML files without sufficient sanitization of embedded script content. When users upload XML files containing XHTML namespace elements with embedded JavaScript, the platform processes these files without proper security checks that would normally prevent execution of malicious code. This creates a persistent XSS vector because the uploaded content remains stored within the application's database or file system and gets served to other users without proper sanitization. The vulnerability specifically targets the journal module's file handling capabilities, which are designed to accept various content formats but fail to properly validate the security implications of XML content that may contain executable scripts.
The operational impact of CVE-2020-37103 extends beyond simple script execution as it enables attackers to bypass standard CSRF protections that typically safeguard against cross-site request forgery attacks. This weakness creates a more dangerous attack surface because authenticated users can leverage the vulnerability to perform actions that would normally require explicit user consent or additional authentication mechanisms. Attackers can craft malicious XML files that, when viewed by other users, execute arbitrary JavaScript code in their browser context, potentially leading to session hijacking, data theft, or privilege escalation within the application. The persistent nature of the vulnerability means that once a malicious file is uploaded, it continues to affect users who access the journal content, making it particularly dangerous for organizations where multiple users interact with journal tools.
Security mitigation strategies for this vulnerability should focus on implementing comprehensive input validation and content sanitization measures within the file upload processing pipeline. Organizations should enforce strict file type validation that prevents XML files with executable script content from being processed, while also implementing proper XML parsing security measures that reject XHTML namespace declarations containing JavaScript code. The implementation of Content Security Policy headers and proper output encoding can provide additional protection layers against XSS exploitation. According to CWE standards, this vulnerability maps to CWE-79 which specifically addresses cross-site scripting flaws, while the ATT&CK framework would categorize this under T1059.007 for scripting and T1566 for phishing techniques that leverage persistent XSS vectors. Organizations should also implement regular security scanning and monitoring of file upload directories to detect and prevent unauthorized malicious file uploads, while ensuring that all DotNetNuke installations are updated to versions that contain proper security patches addressing this specific vulnerability.