CVE-2026-3165: Tenda F453 Buffer Overflow Vulnerability

CVE-2026-3165 Overview

A buffer overflow vulnerability has been identified in the Tenda F453 router firmware version 1.0.0.3. The vulnerability affects the fromSetWifiGusetBasic function within the /goform/AdvSetWrlsafeset endpoint of the httpd component. Remote attackers can exploit this flaw by manipulating the mit_ssid argument, causing a buffer overflow condition that could lead to remote code execution or denial of service.

Critical Impact

This network-accessible buffer overflow vulnerability in Tenda F453 routers allows authenticated attackers to potentially execute arbitrary code or crash the device's web service, compromising network security and device availability.

Affected Products

• Tenda F453 Firmware version 1.0.0.3
• Tenda F453 Hardware

Discovery Timeline

• 2026-02-25 - CVE CVE-2026-3165 published to NVD
• 2026-02-25 - Last updated in NVD database

Technical Details for CVE-2026-3165

Vulnerability Analysis

This vulnerability is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The flaw resides in the HTTP daemon (httpd) service that manages the router's web-based administration interface.

The fromSetWifiGusetBasic function, responsible for handling wireless guest network configuration requests, fails to properly validate the length of the mit_ssid parameter before copying it into a fixed-size buffer. When an attacker supplies an overly long SSID value, the function writes beyond the allocated memory boundary, potentially overwriting adjacent memory regions including return addresses or function pointers.

The vulnerability requires low-privilege authentication but can be triggered remotely over the network without any user interaction. A successful exploit could allow an attacker to execute arbitrary code with the privileges of the httpd service, typically running as root on embedded devices, or cause a denial of service by crashing the web management interface.

Root Cause

The root cause is improper input validation in the fromSetWifiGusetBasic function. The function copies user-supplied data from the mit_ssid HTTP parameter into a stack or heap buffer without verifying that the input length does not exceed the buffer's allocated size. This classic buffer overflow pattern results from missing boundary checks on user-controlled input before memory operations.

Attack Vector

The attack vector is network-based, targeting the /goform/AdvSetWrlsafeset endpoint on the router's web management interface. An authenticated attacker can craft a malicious HTTP request containing an oversized mit_ssid parameter value. When the httpd service processes this request, the buffer overflow condition is triggered.

The vulnerability has been publicly disclosed and exploit details are available through the GitHub Vulnerability Report. Attackers could leverage this information to develop working exploits targeting vulnerable Tenda F453 devices exposed on local networks or, in misconfigured deployments, accessible from the internet.

Detection Methods for CVE-2026-3165

Indicators of Compromise

• Unusual HTTP POST requests to /goform/AdvSetWrlsafeset with abnormally long mit_ssid parameter values
• Repeated crashes or restarts of the httpd service on Tenda F453 devices
• Unexpected modifications to wireless guest network configurations
• Anomalous network traffic patterns from router management interfaces

Detection Strategies

• Monitor HTTP traffic to router management interfaces for requests containing oversized parameter values in wireless configuration endpoints
• Implement web application firewall (WAF) rules to detect and block requests with parameter values exceeding expected SSID length limits (typically 32 bytes)
• Deploy network intrusion detection systems (IDS) with signatures for buffer overflow exploitation attempts targeting embedded device web interfaces
• Enable logging on network devices to capture administrative access attempts and configuration changes

Monitoring Recommendations

• Regularly audit access logs for the router's web management interface to identify unauthorized access attempts
• Implement network segmentation to isolate IoT and network infrastructure devices from general user traffic
• Set up alerts for service disruptions or unexpected reboots of Tenda network equipment
• Monitor for firmware version mismatches across deployed Tenda F453 devices to ensure patching compliance

How to Mitigate CVE-2026-3165

Immediate Actions Required

• Restrict access to the router's web management interface to trusted IP addresses only
• Disable remote management features if not required for operations
• Implement network-level access controls to limit who can reach the administrative interface
• Monitor for firmware updates from Tenda that address this vulnerability

Patch Information

At the time of publication, no official patch has been released by Tenda. Users should monitor the Tenda official website for security updates addressing this vulnerability. Additional technical details and tracking information are available through VulDB #347672.

Workarounds

• Configure firewall rules to block external access to the router's web management interface (typically port 80/443)
• Use strong, unique credentials for router administration to reduce the risk of authenticated exploitation
• Consider replacing vulnerable devices with alternatives if no patch becomes available within an acceptable timeframe
• Implement network monitoring to detect exploitation attempts while awaiting a vendor patch

# Example iptables rules to restrict web management access
# Allow management access only from trusted admin subnet
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