CVE-2026-24426: Tenda AC7 XSS Vulnerability

CVE-2026-24426 Overview

CVE-2026-24426 is a reflected Cross-Site Scripting (XSS) vulnerability affecting Shenzhen Tenda AC7 router firmware version V03.03.03.01_cn and prior versions. The vulnerability exists in the web management interface where user-supplied input is reflected in HTTP responses without adequate output encoding or escaping. This allows attackers to inject arbitrary HTML or JavaScript code that executes in a victim's browser context when they interact with a malicious link.

Critical Impact

Attackers can steal session credentials, hijack administrative sessions, modify router configurations, or redirect victims to malicious sites by exploiting the improper output encoding in the Tenda AC7 web interface.

Affected Products

• Shenzhen Tenda AC7 firmware version V03.03.03.01_cn
• Shenzhen Tenda AC7 firmware versions prior to V03.03.03.01_cn

Discovery Timeline

• 2026-02-03 - CVE-2026-24426 published to NVD
• 2026-02-04 - Last updated in NVD database

Technical Details for CVE-2026-24426

Vulnerability Analysis

This vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation), commonly known as reflected Cross-Site Scripting (XSS). The Tenda AC7 router's web management interface fails to properly encode or sanitize user-supplied input before including it in HTTP responses. When an authenticated or unauthenticated user is tricked into clicking a specially crafted link, the malicious payload is reflected back by the server and executed within the victim's browser session.

The attack requires user interaction, as the victim must navigate to a malicious URL containing the XSS payload. Once executed, the injected JavaScript runs with the same privileges as the legitimate web application, potentially allowing attackers to perform actions on behalf of the victim, steal sensitive information such as session cookies or router credentials, or modify router configuration settings.

Root Cause

The root cause of this vulnerability is improper output encoding in the Tenda AC7 web management interface. When the application generates HTTP responses, it includes user-controllable input directly in the response body without applying appropriate HTML entity encoding or JavaScript escaping. This failure to neutralize special characters such as <, >, ", and ' enables attackers to break out of the intended context and inject executable script content.

Attack Vector

The attack is network-based and requires social engineering to deliver the malicious link to a victim who has access to the router's web interface. An attacker constructs a URL containing a JavaScript payload within a vulnerable parameter. When the victim clicks this link while authenticated to the router's management interface, the malicious script executes in their browser context.

The malicious JavaScript can then access the DOM of the router's management interface, exfiltrate session tokens or credentials to an attacker-controlled server, make configuration changes to the router on behalf of the victim, or redirect the user to phishing pages designed to capture additional credentials. Since the Tenda AC7 is a consumer-grade router, successful exploitation could lead to network compromise, DNS hijacking, or man-in-the-middle attacks affecting all devices on the network.

Detection Methods for CVE-2026-24426

Indicators of Compromise

• HTTP requests to the Tenda AC7 web interface containing URL-encoded script tags or JavaScript event handlers in query parameters
• Unusual outbound connections from the router management interface to external domains
• Unexpected modifications to router DNS settings, firewall rules, or administrative credentials
• Browser developer console logs showing JavaScript execution errors from injected payloads

Detection Strategies

• Monitor network traffic for HTTP requests to the router's web interface containing suspicious patterns such as <script>, javascript:, onerror=, or onload= in URL parameters
• Implement web application firewall (WAF) rules to detect and block common XSS payload patterns targeting network devices
• Review access logs for the router management interface for requests with abnormally long query strings or encoded characters

Monitoring Recommendations

• Enable logging on the Tenda AC7 router if available and regularly review for suspicious access patterns
• Deploy network-level monitoring to detect attempts to access the router's web interface from untrusted sources
• Consider implementing browser-based security extensions for administrators that warn about potentially malicious URLs

How to Mitigate CVE-2026-24426

Immediate Actions Required

• Restrict access to the Tenda AC7 web management interface to trusted internal networks only
• Disable remote management features if not required for operations
• Educate network administrators to avoid clicking links from untrusted sources while authenticated to the router interface
• Consider placing the router management interface behind a VPN to limit exposure

Patch Information

At the time of publication, no vendor patch has been confirmed for this vulnerability. Administrators should monitor the Tenda AC7 Product Page for firmware updates that address this security issue. Additional technical details are available in the VulnCheck Advisory for Tenda AC7 XSS.

Workarounds

• Configure firewall rules to restrict access to the router's web management interface from the LAN only, blocking all external access
• Use network segmentation to isolate the router management interface from general user networks
• Implement Content Security Policy (CSP) headers at the network gateway level if possible to mitigate script injection attacks
• Consider replacing the affected device with a router from a vendor with a more responsive security update process

# Example: Restrict router management access to specific IP addresses using upstream firewall
# Block external access to Tenda AC7 management port (typically 80/443)
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 80 -j DROP
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 443 -j DROP

# Allow management access only from admin workstation
iptables -I FORWARD -s 192.168.1.100 -d 192.168.1.1 -p tcp --dport 80 -j ACCEPT