CVE-2026-24428: Tenda W30e Auth Bypass Vulnerability

CVE-2026-24428 Overview

CVE-2026-24428 is an authorization bypass vulnerability in Shenzhen Tenda W30E V2 firmware that allows authenticated low-privileged users to escalate their privileges to administrator level. The flaw exists in the user management API, where role-based access controls enforced by the web interface can be circumvented by sending crafted requests directly to backend endpoints. This enables attackers to change the administrator account password and gain full administrative control over the affected device.

Critical Impact

Low-privileged authenticated users can escalate to full administrative access by bypassing authorization controls, potentially leading to complete device compromise and network infrastructure takeover.

Affected Products

• Tenda W30E V2 firmware versions up to and including V16.01.0.19(5037)
• Tenda W30E hardware version 2.0
• Tenda W30E Firmware

Discovery Timeline

• 2026-01-26 - CVE-2026-24428 published to NVD
• 2026-01-29 - Last updated in NVD database

Technical Details for CVE-2026-24428

Vulnerability Analysis

This vulnerability represents a classic Incorrect Authorization flaw (CWE-863) where backend API endpoints fail to properly validate user permissions before processing sensitive operations. The Tenda W30E V2 router's web management interface implements role-based access controls at the frontend layer, restricting certain administrative functions from low-privileged users. However, the underlying backend API does not independently verify authorization, creating a security gap that can be exploited by authenticated attackers who bypass the frontend restrictions.

The attack is network-accessible and requires low complexity to execute, as an attacker only needs valid credentials for any user account on the device. Once authenticated, the attacker can directly invoke the password change API endpoint for the administrator account without triggering authorization checks, effectively escalating their privileges to full administrative access.

Root Cause

The root cause of CVE-2026-24428 lies in the improper separation of authorization logic between the frontend web interface and backend API. The firmware developers implemented access controls in the user interface layer rather than enforcing them at the API level. This architectural flaw means that while the web interface may hide or disable administrative functions for low-privileged users, the backend endpoints remain accessible and functional for any authenticated session, regardless of the user's actual privilege level.

Attack Vector

The attack vector for this vulnerability involves an authenticated attacker with low-privilege credentials on the Tenda W30E V2 device. The attacker intercepts or crafts HTTP requests to the user management API endpoint responsible for password changes. By modifying the target account parameter to reference the administrator account and submitting the request directly to the backend (bypassing the web interface's restrictions), the attacker can successfully change the administrator password. This grants them full administrative control over the router, including the ability to modify network configurations, access connected devices, and potentially pivot to other network resources.

The vulnerability does not require user interaction and can be exploited remotely over the network, making it particularly dangerous in environments where the router's management interface is exposed or accessible to untrusted users.

Detection Methods for CVE-2026-24428

Indicators of Compromise

• Unexpected administrator password changes or account lockouts
• API requests to user management endpoints originating from low-privileged user sessions
• Unauthorized configuration changes following low-privileged user authentication
• Anomalous HTTP traffic patterns to backend API endpoints bypassing normal web interface flows

Detection Strategies

• Monitor authentication logs for privilege escalation patterns where low-privileged users suddenly perform administrative actions
• Implement network monitoring to detect direct API calls to sensitive endpoints that bypass the web interface
• Configure alerts for administrator password changes or account modifications
• Review access logs for unusual sequences of API requests from authenticated sessions

Monitoring Recommendations

• Enable verbose logging on the Tenda W30E device if available to capture detailed API access patterns
• Deploy network intrusion detection systems to monitor management interface traffic
• Implement centralized log collection for router management activities
• Establish baseline behavior for administrative operations to identify anomalies

How to Mitigate CVE-2026-24428

Immediate Actions Required

• Restrict network access to the router's management interface to trusted administrators only
• Implement network segmentation to isolate the management interface from general user access
• Review and audit all user accounts on affected devices, removing unnecessary low-privileged accounts
• Monitor for unauthorized configuration changes or password modifications

Patch Information

At the time of publication, no official patch has been released by Tenda for this vulnerability. Organizations should monitor the Tenda W30E Product Page for firmware updates that address CVE-2026-24428. The VulnCheck Advisory on Tenda W30E provides additional technical details and should be monitored for updates regarding remediation status.

Workarounds

• Disable remote management access and only allow local administration through trusted physical connections
• Implement firewall rules to restrict access to the management interface from untrusted network segments
• Use a VPN or jump host to access the management interface, limiting exposure to authenticated users
• Consider replacing affected devices with alternative products if mitigation is not feasible in your environment

# Example firewall rule to restrict management interface access
# Adjust interface and IP ranges according to your network configuration
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP