CVE-2026-3768: Tenda F453 Buffer Overflow Vulnerability

CVE-2026-3768 Overview

A stack-based buffer overflow vulnerability has been identified in the Tenda F453 wireless router firmware version 1.0.0.3. The vulnerability exists in the formWrlExtraSet function within the /goform/WrlExtraSet endpoint. By manipulating the GO argument, an attacker can trigger a buffer overflow condition that may allow for remote code execution or denial of service on the affected device.

Critical Impact

This remotely exploitable vulnerability enables authenticated attackers to execute arbitrary code or cause denial of service on Tenda F453 routers, potentially compromising the entire network segment behind the affected device.

Affected Products

• Tenda F453 Firmware version 1.0.0.3
• Tenda F453 Hardware

Discovery Timeline

• 2026-03-08 - CVE-2026-3768 published to NVD
• 2026-03-09 - Last updated in NVD database

Technical Details for CVE-2026-3768

Vulnerability Analysis

The vulnerability resides in the formWrlExtraSet function responsible for handling wireless configuration settings in the Tenda F453 router. When processing the GO parameter submitted to the /goform/WrlExtraSet endpoint, the function fails to properly validate the length of user-supplied input before copying it to a fixed-size stack buffer.

This represents a classic CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) condition where insufficient boundary checking allows data to overflow beyond allocated memory regions. The network-accessible nature of the vulnerable endpoint combined with the low attack complexity makes this a significant security concern for affected devices.

Root Cause

The root cause is improper input validation in the formWrlExtraSet function. The function accepts the GO argument from HTTP requests without adequately verifying that the input length does not exceed the capacity of the destination stack buffer. This lack of bounds checking allows an attacker to supply an oversized value that overwrites adjacent memory on the stack, including potentially critical control data such as return addresses or saved frame pointers.

Attack Vector

The attack is conducted remotely over the network through the web management interface of the Tenda F453 router. An authenticated attacker can craft a malicious HTTP request to the /goform/WrlExtraSet endpoint with an oversized GO parameter value. When the vulnerable formWrlExtraSet function processes this request, the buffer overflow occurs, potentially allowing the attacker to:

1. Overwrite stack-based control structures to hijack program execution flow
2. Execute arbitrary code in the context of the web server process
3. Cause a denial of service condition by crashing the device

The vulnerability has been publicly disclosed, with technical details available in the GitHub Vulnerability Database Entry. Exploitation requires authenticated access to the router's web interface, though default or weak credentials on consumer routers may lower this barrier significantly.

Detection Methods for CVE-2026-3768

Indicators of Compromise

• Unexpected HTTP POST requests to /goform/WrlExtraSet with abnormally large GO parameter values
• Router crashes, unexpected reboots, or unresponsive web management interface
• Anomalous outbound network traffic from the router indicating potential compromise
• Modified router configurations or unauthorized changes to wireless settings

Detection Strategies

• Implement network intrusion detection rules to identify HTTP requests to /goform/WrlExtraSet containing oversized parameters
• Monitor router logs for repeated authentication attempts followed by crashes or service interruptions
• Deploy web application firewall rules to detect and block requests with excessively long parameter values
• Conduct periodic firmware version audits to identify devices running vulnerable firmware 1.0.0.3

Monitoring Recommendations

• Enable and centralize logging from router web interfaces where supported
• Configure network monitoring to alert on unusual traffic patterns to and from router management interfaces
• Implement baseline monitoring for router availability to detect potential DoS conditions
• Review authentication logs for the router's administrative interface regularly

How to Mitigate CVE-2026-3768

Immediate Actions Required

• Restrict access to the router's web management interface to trusted internal networks only
• Disable remote management features if not required for operations
• Implement strong, unique administrative credentials on all affected devices
• Monitor for firmware updates from Tenda and apply patches when available

Patch Information

As of the last modification date of 2026-03-09, no vendor patch has been publicly announced for this vulnerability. Organizations should monitor the Tenda Official Website for security updates and firmware releases that address CVE-2026-3768. Additional technical details and tracking information can be found at VulDB #349746.

Workarounds

• Restrict management interface access to specific trusted IP addresses using access control lists
• Place the router's management interface on a separate VLAN isolated from general network traffic
• Consider deploying an upstream firewall to filter and inspect traffic destined for the router's web interface
• If feasible, consider replacing affected devices with alternative hardware until a patch is available