CVE-2026-3376: Tenda F453 Buffer Overflow Vulnerability

CVE-2026-3376 Overview

A buffer overflow vulnerability has been identified in the Tenda F453 router firmware version 1.0.0.3. The vulnerability exists within the fromSafeMacFilter function located in the /goform/SafeMacFilter endpoint. By manipulating the page argument, an attacker can trigger a buffer overflow condition that may lead to arbitrary code execution or denial of service on the affected device.

Critical Impact

Remote attackers with low privileges can exploit this buffer overflow vulnerability to potentially gain full control of the router, compromising network security and enabling further attacks on connected devices.

Affected Products

• Tenda F453 Firmware version 1.0.0.3
• Tenda F453 Hardware Device

Discovery Timeline

• 2026-02-28 - CVE-2026-3376 published to NVD
• 2026-03-03 - Last updated in NVD database

Technical Details for CVE-2026-3376

Vulnerability Analysis

This vulnerability is a classic buffer overflow (CWE-119) affecting the web management interface of the Tenda F453 router. The fromSafeMacFilter function fails to properly validate the length of user-supplied input passed through the page parameter before copying it to a fixed-size buffer. When an attacker sends a specially crafted request with an oversized page argument to the /goform/SafeMacFilter endpoint, the function writes data beyond the allocated buffer boundaries, corrupting adjacent memory regions.

The network-accessible nature of this vulnerability makes it particularly dangerous, as attackers can exploit it remotely without requiring physical access to the device. The low attack complexity combined with the ability to impact confidentiality, integrity, and availability makes this a significant security concern for organizations using affected Tenda F453 devices. The exploit has been publicly disclosed, increasing the risk of active exploitation.

Root Cause

The root cause is improper bounds checking in the fromSafeMacFilter function when processing the page parameter from HTTP requests. The function does not validate the input length before performing memory operations, allowing user-controlled data to overflow the destination buffer. This is a common implementation flaw in embedded device firmware where memory safety practices may be overlooked during development.

Attack Vector

The attack can be executed remotely over the network by sending a malicious HTTP request to the /goform/SafeMacFilter endpoint. An attacker with low-level privileges (such as basic authentication to the router's web interface) can craft a request containing an oversized page parameter value. When processed by the vulnerable fromSafeMacFilter function, this triggers the buffer overflow condition.

The vulnerability manifests when the page argument exceeds expected bounds, causing memory corruption that can be leveraged to overwrite critical data structures such as return addresses, function pointers, or other control flow data. See the GitHub Vulnerability Documentation for detailed technical analysis of the exploitation mechanism.

Detection Methods for CVE-2026-3376

Indicators of Compromise

• Unusual HTTP requests to /goform/SafeMacFilter with abnormally large page 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 administrative access

Detection Strategies

• Deploy network intrusion detection rules to identify malformed requests targeting /goform/SafeMacFilter
• Monitor HTTP traffic to Tenda F453 devices for requests containing oversized parameter values
• Implement application-layer firewall rules to block suspicious patterns in page parameter content
• Enable logging on the router and correlate logs for crash events or authentication anomalies

Monitoring Recommendations

• Establish baseline traffic patterns to and from Tenda F453 devices to identify deviations
• Configure alerts for router restarts or management interface availability issues
• Review network logs regularly for reconnaissance activity targeting router endpoints
• Segment IoT and network infrastructure devices to limit lateral movement potential

How to Mitigate CVE-2026-3376

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 network segmentation to isolate Tenda F453 devices from critical infrastructure
• Monitor for exploitation attempts using the detection strategies outlined above

Patch Information

At the time of publication, no official patch has been released by Tenda for this vulnerability. Organizations should monitor the Tenda Official Website for firmware updates that address CVE-2026-3376. Additional technical details are available through VulDB #348261.

Workarounds

• Restrict web management interface access using firewall rules to allow only trusted IP addresses
• Disable the web management interface entirely if feasible and manage the device through alternative methods
• Place vulnerable Tenda F453 routers behind a VPN to limit attack surface exposure
• Consider replacing affected devices with hardware that receives timely security updates

# Example: Restrict access to router management interface using iptables
# 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