CVE-2026-7053: Tenda F456 Buffer Overflow Vulnerability

CVE-2026-7053 Overview

A buffer overflow vulnerability has been discovered in the Tenda F456 router firmware version 1.0.0.5. This security flaw affects the frmL7ProtForm function within the /goform/L7Prot endpoint of the httpd component. By manipulating the page argument, an attacker can trigger a buffer overflow condition. This vulnerability can be exploited remotely over the network, posing significant risk to affected devices. The exploit has been publicly disclosed and may be actively leveraged in attacks targeting vulnerable Tenda routers.

Critical Impact
Remote attackers can exploit this buffer overflow vulnerability to potentially execute arbitrary code or cause denial of service on Tenda F456 routers running firmware version 1.0.0.5.

Affected Products

Tenda F456 Firmware version 1.0.0.5
Tenda F456 Hardware devices

Discovery Timeline

2026-04-26 - CVE-2026-7053 published to NVD
2026-04-29 - Last updated in NVD database

Technical Details for CVE-2026-7053

Vulnerability Analysis

This vulnerability is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The flaw exists in the httpd service's handling of user-supplied input through the frmL7ProtForm function. When processing requests to the /goform/L7Prot endpoint, the function fails to properly validate the length of the page argument before copying it into a fixed-size buffer.

The vulnerability can be triggered remotely over the network and requires low-privileged authentication. Upon successful exploitation, an attacker could achieve high impact across confidentiality, integrity, and availability of the affected device. This could result in arbitrary code execution with the privileges of the httpd service, complete device compromise, or denial of service conditions.

Root Cause

The root cause of this vulnerability is insufficient bounds checking in the frmL7ProtForm function when processing the page parameter. The httpd component fails to validate that user-supplied input does not exceed the allocated buffer size, allowing an attacker to overflow memory boundaries. This improper restriction of operations within memory bounds (CWE-119) is a common vulnerability pattern in embedded device firmware where memory-safe programming practices may not be consistently applied.

Attack Vector

The attack vector is network-based, allowing remote exploitation without requiring physical access to the device. An authenticated attacker with low privileges can send a specially crafted HTTP request to the /goform/L7Prot endpoint with an oversized page parameter. The malicious input overflows the target buffer, potentially overwriting adjacent memory regions including return addresses or function pointers.

The vulnerability has been publicly documented with proof-of-concept materials available in the GitHub PoC Repository. Attackers can reference this documentation to craft exploit payloads targeting vulnerable Tenda F456 devices.

Detection Methods for CVE-2026-7053

Indicators of Compromise

Unexpected HTTP POST requests to /goform/L7Prot with unusually large page parameter values
Httpd service crashes or restarts on Tenda F456 devices
Anomalous network traffic patterns targeting router management interfaces
Device instability or unexpected reboots without administrative action

Detection Strategies

Monitor HTTP traffic to Tenda F456 management interfaces for requests to /goform/L7Prot with abnormally long parameter values
Implement network intrusion detection rules to identify buffer overflow attack patterns targeting Tenda devices
Deploy web application firewall rules to block requests exceeding normal parameter length thresholds

Monitoring Recommendations

Enable logging on network perimeter devices to capture traffic to router management interfaces
Monitor for httpd service crashes in device logs that may indicate exploitation attempts
Implement network segmentation to isolate IoT and router management interfaces from untrusted networks

How to Mitigate CVE-2026-7053

Immediate Actions Required

Restrict network access to the Tenda F456 management interface to trusted IP addresses only
Disable remote management if not explicitly required for operations
Place the router's management interface behind a firewall or VPN
Monitor the Tenda vendor website for firmware updates addressing this vulnerability

Patch Information

At the time of publication, no official patch has been released by Tenda to address this vulnerability. Organizations should monitor the Tenda Company Website and security advisories for firmware updates. Additional technical details and vulnerability tracking information can be found at VulDB #359626.

Workarounds

Implement strict network access controls to limit management interface access to authorized administrators only
Use firewall rules to block external access to the /goform/L7Prot endpoint
Consider deploying a reverse proxy with input validation in front of the device management interface
If possible, replace vulnerable devices with alternatives that have active security support

bash

# Example firewall configuration to restrict management access
# Block external access to Tenda 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