CVE-2026-3166: Tenda F453 Buffer Overflow Vulnerability

CVE-2026-3166 Overview

A buffer overflow vulnerability has been identified in Tenda F453 firmware version 1.0.0.3. The vulnerability exists within the fromRouteStatic function located in the /goform/RouteStatic endpoint of the httpd component. An attacker can exploit this flaw by manipulating the page argument, leading to a buffer overflow condition. This vulnerability can be exploited remotely and an exploit has been publicly disclosed, increasing the risk of active exploitation.

Critical Impact

Remote attackers can exploit this buffer overflow to potentially execute arbitrary code or cause denial of service on vulnerable Tenda F453 routers, compromising network security and device integrity.

Affected Products

• Tenda F453 Firmware version 1.0.0.3
• Tenda F453 Hardware

Discovery Timeline

• 2026-02-25 - CVE-2026-3166 published to NVD
• 2026-02-25 - Last updated in NVD database

Technical Details for CVE-2026-3166

Vulnerability Analysis

This vulnerability is classified as CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer), commonly known as a buffer overflow. The flaw exists in the embedded web server (httpd) component of Tenda F453 routers, specifically within the fromRouteStatic function that handles requests to the /goform/RouteStatic endpoint.

When processing the page argument, the function fails to properly validate the length of user-supplied input before copying it to a fixed-size buffer. This allows an attacker to supply oversized input that exceeds the allocated buffer space, corrupting adjacent memory regions. Depending on the memory layout and protections in place, this could lead to arbitrary code execution, allowing complete compromise of the device.

The vulnerability is accessible over the network without requiring any user interaction, making it particularly dangerous for exposed router management interfaces.

Root Cause

The root cause of this vulnerability is improper input validation in the fromRouteStatic function. The function accepts the page parameter from HTTP requests without adequately checking the input length against the destination buffer size. This lack of bounds checking allows memory corruption when attackers submit crafted requests with oversized page values.

The underlying issue stems from unsafe string handling practices common in embedded C/C++ firmware, where functions like strcpy() or sprintf() may be used without proper length validation.

Attack Vector

The attack vector is network-based, targeting the httpd web server component running on the Tenda F453 router. An attacker with network access to the router's management interface can send a specially crafted HTTP request to the /goform/RouteStatic endpoint with a malicious page parameter value.

The exploitation requires low-privilege access (authenticated user level) but does not require any user interaction. A successful exploit could result in high impact to confidentiality, integrity, and availability of the device, potentially allowing the attacker to execute arbitrary code with the privileges of the httpd process.

Technical details and proof-of-concept information are available in the GitHub Vulnerability Repository.

Detection Methods for CVE-2026-3166

Indicators of Compromise

• Unusual HTTP POST requests to /goform/RouteStatic with abnormally long page parameter values
• Unexpected httpd process crashes or restarts on Tenda F453 devices
• Anomalous network traffic patterns originating from router management ports
• Device configuration changes not initiated by authorized administrators

Detection Strategies

• Monitor network traffic for HTTP requests to /goform/RouteStatic endpoints on Tenda devices with unusually large payloads
• Implement IDS/IPS rules to detect buffer overflow attack patterns targeting Tenda router web interfaces
• Configure logging on network segments containing Tenda F453 devices to capture suspicious HTTP requests
• Deploy endpoint detection capabilities that can identify memory corruption exploitation attempts

Monitoring Recommendations

• Audit access logs for the router's web management interface for suspicious request patterns
• Monitor device stability and unexpected reboots which may indicate exploitation attempts
• Implement network segmentation to limit exposure of router management interfaces
• Review VulDB entries (VulDB #347673) for updated threat intelligence

How to Mitigate CVE-2026-3166

Immediate Actions Required

• Restrict access to the router's web management interface to trusted networks or IP addresses only
• Disable remote management access if not required for operations
• Implement firewall rules to block external access to the /goform/ endpoints
• Monitor for any available firmware updates from Tenda

Patch Information

As of the publication date, no official patch has been released by Tenda for this vulnerability. Organizations using affected Tenda F453 devices should monitor the Tenda Official Website for security updates and firmware releases. Until a patch is available, implementing the workarounds below is strongly recommended.

Additional technical details can be found in the VulDB CTI entry.

Workarounds

• Disable the httpd web interface entirely if remote management is not required
• Implement network-level access controls to restrict management interface access to trusted IP addresses
• Deploy a web application firewall (WAF) in front of the device to filter malicious requests
• Consider replacing vulnerable devices with alternative hardware that receives regular security updates

# Example: Firewall rule to restrict access to management interface
# Block external access to router management ports
iptables -A INPUT -p tcp --dport 80 -s ! 192.168.1.0/24 -j DROP
iptables -A INPUT -p tcp --dport 443 -s ! 192.168.1.0/24 -j DROP