CVE-2026-3378: Tenda F453 Buffer Overflow Vulnerability

CVE-2026-3378 Overview

A buffer overflow vulnerability has been identified in Tenda F453 router firmware version 1.0.0.3. This security flaw affects the fromqossetting function within the /goform/qossetting endpoint. By manipulating the qos argument, an attacker can trigger a buffer overflow condition. The vulnerability is remotely exploitable, making it a significant security concern for organizations and individuals using affected Tenda F453 devices. The exploit has been publicly disclosed and may be actively used.

Critical Impact

Remote attackers can exploit this buffer overflow vulnerability to potentially execute arbitrary code, crash the device, or gain unauthorized access to the router, compromising network security and all connected devices.

Affected Products

• Tenda F453 Hardware
• Tenda F453 Firmware version 1.0.0.3

Discovery Timeline

• 2026-03-01 - CVE-2026-3378 published to NVD
• 2026-03-03 - Last updated in NVD database

Technical Details for CVE-2026-3378

Vulnerability Analysis

This buffer overflow vulnerability (CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer) exists in the Tenda F453 router's web management interface. The vulnerable function fromqossetting fails to properly validate the length of user-supplied input through the qos parameter before copying it into a fixed-size memory buffer. When an attacker sends a specially crafted HTTP request with an oversized qos argument to the /goform/qossetting endpoint, the function writes beyond the allocated buffer boundaries, corrupting adjacent memory regions.

This type of memory corruption can lead to various exploitation scenarios, including denial of service through device crashes, potential arbitrary code execution if an attacker can control the overwritten memory contents, or privilege escalation within the device context. The network-accessible nature of this endpoint significantly increases the attack surface since no physical access to the device is required.

Root Cause

The root cause of CVE-2026-3378 is improper input validation and bounds checking in the fromqossetting function. The firmware fails to verify that user-supplied data in the qos parameter does not exceed the expected buffer size before performing memory operations. This is a common vulnerability pattern in embedded device firmware where memory-safe programming practices are not consistently applied.

Attack Vector

The attack vector for this vulnerability is network-based. An authenticated attacker can exploit this flaw by sending a malicious HTTP request to the vulnerable /goform/qossetting endpoint on the router's web management interface. The attack does not require user interaction and can be launched remotely from any network position that can reach the router's management interface.

The vulnerability is exploited by providing an excessively long value for the qos argument in a form submission to the affected endpoint. When the router processes this request, the oversized input overflows the designated buffer, potentially allowing the attacker to overwrite critical memory structures including return addresses or function pointers.

For technical details and proof-of-concept information, refer to the GitHub Vulnerability Summary.

Detection Methods for CVE-2026-3378

Indicators of Compromise

• Unusual or repeated HTTP POST requests to /goform/qossetting with abnormally large parameter values
• Router crashes, unexpected reboots, or unresponsive web management interface
• Anomalous network traffic patterns originating from or directed to the router
• Unexpected changes to router configuration or QoS settings

Detection Strategies

• Implement network intrusion detection rules to identify HTTP requests to /goform/qossetting with oversized qos parameters
• Monitor router logs for repeated authentication attempts or unusual access patterns to the web management interface
• Deploy web application firewall rules to filter requests with excessively long parameter values
• Use firmware integrity monitoring to detect unauthorized modifications

Monitoring Recommendations

• Enable logging on the Tenda F453 router and forward logs to a centralized SIEM solution
• Monitor network traffic for anomalous communication patterns involving the router's management ports
• Set up alerts for router availability issues that may indicate exploitation attempts
• Periodically review router configuration for unauthorized changes

How to Mitigate CVE-2026-3378

Immediate Actions Required

• Restrict access to the router's web management interface to trusted IP addresses only
• Disable remote management access from the WAN interface if not required
• Place the router behind a properly configured firewall that limits access to management ports
• Monitor for and apply any firmware updates from Tenda as soon as available

Patch Information

At the time of this writing, no official patch from Tenda has been identified in the available CVE data. Organizations should monitor the Tenda Official Website and security advisories for firmware updates that address this vulnerability. Additional technical details are available through VulDB.

Workarounds

• Disable the web management interface entirely if not needed for ongoing administration
• Implement network segmentation to isolate the router management interface from untrusted networks
• Use a VPN for remote administration rather than exposing the management interface directly
• Configure access control lists (ACLs) to restrict which hosts can communicate with the router's management services

# Example network access restriction (adjust for your firewall)
# Block external access to router management interface
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP