CVE-2026-24434: Tenda AC7 Router CSRF Vulnerability

CVE-2026-24434 Overview

Shenzhen Tenda AC7 firmware version V03.03.03.01_cn and prior contains a Cross-Site Request Forgery (CSRF) vulnerability in its web management interface. The router's administrative interface fails to implement proper CSRF protections, including anti-CSRF tokens and robust origin validation. This security flaw enables attackers to craft malicious web pages or links that, when visited by an authenticated administrator, can execute unauthorized state-changing requests against the router's configuration.

Critical Impact

An attacker can trick authenticated administrators into unknowingly modifying router settings, potentially compromising network security, changing DNS configurations, creating backdoor accounts, or disabling security features.

Affected Products

• Shenzhen Tenda AC7 firmware version V03.03.03.01_cn
• Shenzhen Tenda AC7 firmware versions prior to V03.03.03.01_cn
• Tenda AC7 wireless routers with vulnerable web management interfaces

Discovery Timeline

• 2026-02-03 - CVE CVE-2026-24434 published to NVD
• 2026-02-04 - Last updated in NVD database

Technical Details for CVE-2026-24434

Vulnerability Analysis

This vulnerability falls under CWE-352 (Cross-Site Request Forgery), a common web application security weakness. The Tenda AC7 router's web management interface processes administrative requests without verifying their origin or including session-specific tokens that would confirm the legitimacy of user-initiated actions.

When an administrator is logged into the router's web interface and simultaneously browses other websites, a malicious page can submit hidden form requests or trigger JavaScript-based HTTP requests to the router's administrative endpoints. Because the browser automatically includes authentication cookies with these requests, and the router lacks CSRF validation mechanisms, these forged requests are processed as legitimate administrative commands.

The network-based attack vector with low complexity makes this vulnerability accessible to remote attackers, though successful exploitation requires user interaction—specifically, the victim must be logged into the router's admin panel while visiting a malicious site.

Root Cause

The root cause of CVE-2026-24434 is the complete absence of CSRF protection mechanisms in the Tenda AC7's web management interface. Properly secured web applications implement several defensive measures including:

• Anti-CSRF tokens: Unique, session-bound tokens included in forms that must be validated server-side
• Origin header validation: Checking the Origin and Referer headers to ensure requests originate from the same domain
• SameSite cookie attributes: Cookie flags that prevent browsers from sending cookies with cross-site requests

The Tenda AC7 firmware implements none of these protections, leaving all administrative functions vulnerable to cross-site request forgery attacks.

Attack Vector

The attack scenario involves the following steps:

1. The attacker identifies an authenticated administrator of a Tenda AC7 router
2. The attacker crafts a malicious webpage containing hidden forms or scripts targeting the router's administrative endpoints
3. The attacker delivers this malicious page to the victim through phishing, watering hole attacks, or malicious advertisements
4. When the victim (who is logged into their router) visits the malicious page, the browser automatically submits requests to the router
5. The router processes these requests as legitimate administrative commands, executing the attacker's desired configuration changes

The vulnerability can be exploited by embedding malicious HTML forms with auto-submit JavaScript or by using XMLHttpRequest/fetch API calls to target known router administration endpoints. Common attack payloads include changing DNS servers to attacker-controlled addresses, modifying WiFi credentials, creating administrative backdoor accounts, or disabling firewall rules.

Detection Methods for CVE-2026-24434

Indicators of Compromise

• Unexpected configuration changes on Tenda AC7 routers, particularly DNS settings, firewall rules, or administrative credentials
• New administrative accounts appearing without authorization
• Modified WiFi network names (SSIDs) or passwords
• Router logs showing administrative actions during times when no legitimate administration was performed
• Users reporting being redirected to suspicious websites when browsing (indicating DNS hijacking)

Detection Strategies

• Monitor router configuration files for unauthorized modifications using configuration management tools
• Implement network monitoring to detect unusual traffic patterns to and from the router's management interface
• Deploy web proxy or firewall rules to detect cross-origin requests targeting internal router IP addresses
• Review browser histories and network logs for connections to known malicious domains that may host CSRF payloads
• Set up alerts for router configuration backups showing unexpected changes

Monitoring Recommendations

• Enable and regularly review router access logs for administrative interface activity
• Configure network intrusion detection systems to alert on suspicious HTTP requests to the router's management ports
• Implement scheduled configuration audits comparing current settings against known-good baselines
• Monitor for DNS query anomalies that could indicate DNS configuration tampering
• Deploy endpoint detection solutions on administrator workstations to identify malicious web content

How to Mitigate CVE-2026-24434

Immediate Actions Required

• Log out of the router's administrative interface when not actively performing configuration tasks
• Access the router's management interface only from a dedicated browser session with no other tabs open
• Use network segmentation to restrict access to the router's management interface from trusted VLANs only
• Consider blocking external access to the router's web management port (typically TCP 80 or 443)
• Regularly audit router configurations for unauthorized changes

Patch Information

As of the last NVD update on 2026-02-04, no official firmware patch has been released by Tenda to address this CSRF vulnerability. Administrators should monitor the Tenda AC7 Product Page for firmware updates and the VulnCheck Advisory on Tenda AC7 for additional guidance.

Workarounds

• Restrict management interface access to specific IP addresses or MAC addresses when possible
• Disable remote management capabilities if not required for operations
• Use browser isolation techniques when accessing the router's administrative interface
• Implement a separate management network with strict access controls for router administration
• Consider deploying a third-party firewall or UTM device in front of the router to add additional protection layers

# Example: Restrict management access using iptables on an upstream device
# Block external access to router management interface (adjust IP as needed)
iptables -A FORWARD -d 192.168.0.1 -p tcp --dport 80 -j DROP
iptables -A FORWARD -d 192.168.0.1 -p tcp --dport 443 -j DROP

# Allow management access only from trusted admin workstation
iptables -I FORWARD -s 192.168.0.100 -d 192.168.0.1 -p tcp --dport 80 -j ACCEPT
iptables -I FORWARD -s 192.168.0.100 -d 192.168.0.1 -p tcp --dport 443 -j ACCEPT