CVE-2026-4551: Tenda F453 Buffer Overflow Vulnerability

CVE-2026-4551 Overview

A stack-based buffer overflow vulnerability has been identified in Tenda F453 router firmware version 1.0.0.3. This vulnerability exists in the fromSafeClientFilter function located in the /goform/SafeClientFilter endpoint of the Parameters Handler component. By manipulating the menufacturer or Go arguments, an attacker can trigger a stack-based buffer overflow condition, potentially leading to arbitrary code execution or denial of service on the affected device.

Critical Impact

This remotely exploitable buffer overflow vulnerability in Tenda F453 routers allows attackers to compromise network infrastructure devices, potentially gaining control over the entire network segment or using the device as a pivot point for further attacks.

Affected Products

• Tenda F453 Firmware Version 1.0.0.3

Discovery Timeline

• 2026-03-22 - CVE-2026-4551 published to NVD
• 2026-03-23 - Last updated in NVD database

Technical Details for CVE-2026-4551

Vulnerability Analysis

This vulnerability is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer), which indicates that the affected function fails to properly validate the boundaries of input data before performing memory operations. The fromSafeClientFilter function processes user-supplied input from the menufacturer and Go parameters without adequate bounds checking, allowing an attacker to overflow the stack buffer.

The vulnerability is remotely exploitable over the network, requiring only low-level authentication to execute. The impact spans across confidentiality, integrity, and availability, as successful exploitation could allow an attacker to execute arbitrary code with the privileges of the web service, modify device configuration, or crash the device entirely.

Root Cause

The root cause of this vulnerability lies in the improper handling of user-supplied input within the fromSafeClientFilter function. The function copies data from the menufacturer or Go HTTP parameters directly into a fixed-size stack buffer without verifying that the input length does not exceed the buffer's capacity. This classic buffer overflow pattern allows attackers to overwrite adjacent stack memory, including the function's return address.

Attack Vector

The attack can be carried out remotely over the network by sending a specially crafted HTTP request to the /goform/SafeClientFilter endpoint. An attacker with low-level privileges on the device can submit an overly long string in the menufacturer or Go parameter, causing the stack buffer to overflow.

The exploitation mechanism involves overwriting the saved return address on the stack with a pointer to attacker-controlled shellcode or a ROP (Return-Oriented Programming) gadget chain. Given that embedded devices like routers often lack modern exploit mitigations such as ASLR or stack canaries, successful exploitation is more reliable. Technical details regarding the vulnerability are available in the GitHub Vulnerability Database Entry.

Detection Methods for CVE-2026-4551

Indicators of Compromise

• Unexpected HTTP POST requests to /goform/SafeClientFilter with abnormally large parameter values
• Router crashes or unexpected reboots following web management interface access
• Unauthorized configuration changes on the Tenda F453 device
• Unusual outbound network connections originating from the router

Detection Strategies

• Monitor HTTP traffic to the router's management interface for requests containing oversized menufacturer or Go parameters
• Implement network intrusion detection rules to identify buffer overflow exploit patterns targeting Tenda devices
• Review router logs for repeated authentication attempts followed by configuration changes
• Deploy honeypot routers with vulnerable firmware to detect active exploitation attempts

Monitoring Recommendations

• Enable logging on the Tenda F453 device and forward logs to a centralized SIEM for analysis
• Monitor for unauthorized access attempts to the device's web management interface
• Track firmware version across all network devices to identify vulnerable deployments
• Implement network segmentation to isolate IoT and network infrastructure devices from general user traffic

How to Mitigate CVE-2026-4551

Immediate Actions Required

• Restrict access to the router's web management interface to trusted IP addresses only
• Disable remote management functionality if not required for operations
• Place the Tenda F453 behind a firewall that blocks external access to the management interface
• Monitor the device for signs of compromise and consider network isolation

Patch Information

At the time of publication, no official patch from Tenda has been referenced in the available CVE data. Organizations should monitor the Tenda Official Website for firmware updates addressing this vulnerability. Additionally, technical details and updates can be tracked via the VulDB Entry #352378.

Workarounds

• Configure firewall rules to restrict access to the /goform/SafeClientFilter endpoint
• Implement network-level access controls to limit management interface access to administrator workstations only
• Consider replacing vulnerable devices with alternatives that have active security support
• Use a VPN for remote management access instead of exposing the management interface directly

# Example iptables rule to restrict management interface access
# Allow only trusted admin IP to access router management port
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.100 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP

# Block external access to vulnerable endpoint
iptables -A INPUT -p tcp --dport 80 -i eth0 -j DROP