CVE-2026-24837: DNN (DotNetNuke) XSS Vulnerability

CVE-2026-24837 Overview

CVE-2026-24837 is a Cross-Site Scripting (XSS) vulnerability affecting DNN (formerly DotNetNuke), an open-source web content management platform (CMS) in the Microsoft ecosystem. Starting in version 9.0.0 and prior to versions 9.13.10 and 10.2.0, a module friendly name could include scripts that will run during some module operations in the Persona Bar. This allows attackers to inject and execute malicious scripts in the context of authenticated administrative users.

Critical Impact

Successful exploitation could allow attackers to execute arbitrary JavaScript code in the context of administrative users managing modules through the Persona Bar, potentially leading to session hijacking, privilege escalation, or unauthorized administrative actions.

Affected Products

• DNN (DotNetNuke) versions 9.0.0 through 9.13.9
• DNN (DotNetNuke) versions 10.0.0 through 10.1.x

Discovery Timeline

• 2026-01-28 - CVE CVE-2026-24837 published to NVD
• 2026-01-29 - Last updated in NVD database

Technical Details for CVE-2026-24837

Vulnerability Analysis

This vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation), commonly known as Cross-Site Scripting (XSS). The flaw exists in how DNN processes module friendly names within the Persona Bar administrative interface. When administrators interact with modules—such as viewing, editing, or managing them—the module friendly name is rendered without proper sanitization, allowing embedded script content to execute in the browser context.

The attack requires network access and targets authenticated administrators through manipulation of module metadata. Due to the change in scope indicated in the vulnerability characteristics, successful exploitation can impact resources beyond the vulnerable component itself, potentially affecting the confidentiality, integrity, and availability of the entire CMS installation.

Root Cause

The root cause is improper input validation and output encoding of the module friendly name field. When module data is stored and subsequently rendered in the Persona Bar interface, the application fails to properly sanitize or encode special characters that could be interpreted as HTML or JavaScript. This allows malicious script content embedded in the friendly name to be executed when the data is displayed to administrative users.

Attack Vector

The attack vector is network-based and requires the attacker to have high privileges (such as the ability to create or modify modules) along with user interaction from a victim administrator. The attacker would craft a module with a malicious friendly name containing JavaScript code. When an administrator subsequently views or interacts with this module through the Persona Bar interface, the embedded script executes in their browser session.

This stored XSS attack pattern is particularly dangerous in CMS environments as administrative sessions typically have elevated privileges. The injected script could potentially steal session tokens, modify site content, create new administrative accounts, or perform other unauthorized actions with the victim's privileges.

Detection Methods for CVE-2026-24837

Indicators of Compromise

• Unusual JavaScript or HTML content in module friendly names within the DNN database
• Unexpected script execution or browser behavior when administrators access the Persona Bar
• Audit logs showing modifications to module metadata containing script tags or event handlers
• Reports from administrators experiencing unusual redirects or session behavior

Detection Strategies

• Monitor and audit module creation and modification events for suspicious content patterns
• Implement Content Security Policy (CSP) headers to detect and block inline script execution
• Review database records in module-related tables for entries containing <script>, javascript:, or event handler attributes
• Deploy web application firewall (WAF) rules to detect XSS payloads in module management requests

Monitoring Recommendations

• Enable detailed logging for Persona Bar administrative operations
• Configure alerts for module metadata changes containing HTML or script patterns
• Monitor for anomalous administrative session activity that may indicate session hijacking
• Implement browser-side monitoring for unexpected script execution in administrative interfaces

How to Mitigate CVE-2026-24837

Immediate Actions Required

• Upgrade DNN installations to version 9.13.10 or 10.2.0 immediately
• Audit existing modules for suspicious friendly names containing script content
• Review administrative user activity logs for signs of compromise
• Consider temporarily restricting module creation and modification privileges until patching is complete

Patch Information

DNN has released security patches addressing this vulnerability. Affected organizations should upgrade to:

• Version 9.13.10 for the 9.x branch
• Version 10.2.0 for the 10.x branch

Detailed patch information and upgrade instructions are available in the GitHub Security Advisory.

Workarounds

• Implement strict Content Security Policy (CSP) headers to mitigate script execution risks
• Restrict module creation and editing privileges to only essential trusted administrators
• Deploy a Web Application Firewall (WAF) with XSS detection rules for administrative endpoints
• Conduct regular audits of module metadata for suspicious content patterns

# Example CSP header configuration for IIS web.config
# Add to system.webServer/httpProtocol/customHeaders section
# <add name="Content-Security-Policy" value="default-src 'self'; script-src 'self'" />