CVE-2026-4845 Overview
A Cross-Site Scripting (XSS) vulnerability has been identified in dameng100 muucmf version 1.9.5.20260309. The vulnerability exists in an unknown function within the file /admin/Member/index.html, where improper handling of the Search argument allows attackers to inject malicious scripts. This flaw can be exploited remotely, enabling attackers to execute arbitrary JavaScript code in the context of a victim's browser session.
Critical Impact
Remote attackers can exploit this XSS vulnerability to steal session cookies, hijack user accounts, deface web content, or redirect administrators to malicious sites. The vendor was contacted but did not respond to disclosure attempts.
Affected Products
- dameng100 muucmf 1.9.5.20260309
Discovery Timeline
- 2026-03-26 - CVE CVE-2026-4845 published to NVD
- 2026-03-26 - Last updated in NVD database
Technical Details for CVE-2026-4845
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 resides in the administrative member management interface of the muucmf content management framework. When a user supplies input through the Search parameter on the /admin/Member/index.html endpoint, the application fails to properly sanitize or encode the input before reflecting it back in the HTML response.
The network-accessible nature of this vulnerability means that an attacker can craft a malicious URL containing JavaScript payload and trick an authenticated administrator into clicking it. Once executed, the injected script runs within the trusted context of the application, potentially compromising the administrator's session.
Root Cause
The root cause of this vulnerability is insufficient input validation and output encoding in the search functionality of the member administration page. The application directly incorporates user-supplied data from the Search parameter into the rendered HTML without proper sanitization, allowing script tags and JavaScript event handlers to be interpreted and executed by the browser.
Attack Vector
The attack vector is network-based, requiring user interaction. An attacker would typically craft a malicious URL containing an XSS payload in the Search parameter and distribute it through phishing emails, social engineering, or by embedding it on a compromised website. When an authenticated administrator clicks the link, the malicious script executes in their browser session with full access to the application's DOM and cookies.
The vulnerability has been publicly documented and a proof-of-concept has been published. Technical details and exploitation methods are available in the GitHub XSS Vulnerability Post.
Detection Methods for CVE-2026-4845
Indicators of Compromise
- Suspicious HTTP requests to /admin/Member/index.html containing script tags, JavaScript event handlers, or encoded payloads in the Search parameter
- Unusual URL patterns with <script>, javascript:, onerror=, or other XSS payload signatures in query strings
- Web server logs showing requests with HTML-encoded characters (%3C, %3E, %22) in the Search parameter
Detection Strategies
- Deploy Web Application Firewall (WAF) rules to detect and block common XSS patterns in HTTP requests targeting the admin member interface
- Implement Content Security Policy (CSP) headers to restrict inline script execution and detect policy violations
- Monitor authentication logs for unusual session activity following access to the vulnerable endpoint
Monitoring Recommendations
- Enable detailed logging for all requests to administrative endpoints, particularly /admin/Member/index.html
- Configure alerts for multiple rapid requests to the vulnerable endpoint from different source IPs
- Review web server access logs regularly for suspicious query string patterns containing potential XSS payloads
How to Mitigate CVE-2026-4845
Immediate Actions Required
- Restrict access to the /admin/Member/index.html endpoint to trusted IP addresses only using firewall rules or access control lists
- Implement a Web Application Firewall (WAF) with XSS detection rules to filter malicious input
- Educate administrators about phishing attacks and the risks of clicking untrusted links while authenticated
- Consider temporarily disabling the search functionality on the member administration page until a patch is available
Patch Information
No official patch is currently available from the vendor. The vendor was contacted about this disclosure but did not respond. Organizations should monitor the VulDB entry for updates on potential fixes. Consider implementing compensating controls or migrating to an alternative CMS solution if the application is critical to operations.
Workarounds
- Apply strict input validation on the Search parameter by implementing server-side filtering that rejects or encodes HTML special characters (<, >, ", ', &)
- Implement HTTP-only and Secure flags on session cookies to reduce the impact of successful XSS attacks
- Deploy Content Security Policy (CSP) headers with script-src 'self' to prevent inline script execution
- Use output encoding libraries to ensure all user-supplied data is properly escaped before being rendered in HTML responses
# Example: Apache .htaccess configuration to restrict admin access by IP
<Location /admin/>
Require ip 192.168.1.0/24
Require ip 10.0.0.0/8
</Location>
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
