CVE-2026-7030: Tenda F456 Firmware Buffer Overflow Flaw

CVE-2026-7030 Overview

A buffer overflow vulnerability has been identified in Tenda F456 router firmware version 1.0.0.5. This vulnerability affects the fromRouteStatic function within the /goform/RouteStatic endpoint. By manipulating the page argument, an attacker can trigger a buffer overflow condition that can be exploited remotely. The exploit details have been publicly disclosed, increasing the urgency for affected users to take protective measures.

Critical Impact
Remote attackers with low-level privileges can exploit this buffer overflow to potentially achieve code execution or cause denial of service on affected Tenda F456 routers, compromising network security at the perimeter.

Affected Products

Tenda F456 Firmware version 1.0.0.5
Tenda F456 Hardware

Discovery Timeline

2026-04-26 - CVE-2026-7030 published to NVD
2026-04-30 - Last updated in NVD database

Technical Details for CVE-2026-7030

Vulnerability Analysis

This buffer overflow vulnerability (CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer) resides in the web management interface of the Tenda F456 router. The vulnerable function fromRouteStatic fails to properly validate the length of user-supplied input passed through the page parameter before copying it into a fixed-size memory buffer.

When a malicious request is sent to the /goform/RouteStatic endpoint with an oversized page argument, the function writes data beyond the allocated buffer boundaries. This memory corruption can overwrite adjacent memory regions including stack return addresses, function pointers, or other critical data structures.

The attack can be initiated remotely over the network, and the publicly disclosed nature of this vulnerability significantly increases the risk of exploitation in the wild. Authenticated access with low privileges is required to reach the vulnerable endpoint, which is typically accessible through the router's web administration interface.

Root Cause

The root cause of CVE-2026-7030 is the lack of proper bounds checking in the fromRouteStatic function when processing the page parameter. The firmware code does not validate that the input length fits within the destination buffer before performing memory copy operations. This is a classic buffer overflow pattern commonly found in embedded device firmware where secure coding practices may not be consistently applied.

Attack Vector

The attack is network-based and targets the router's web management interface. An attacker with low-level authenticated access to the router can craft a malicious HTTP request to the /goform/RouteStatic endpoint with an oversized page parameter value. The attack requires no user interaction and can be executed remotely.

The exploitation flow involves:

Authenticating to the router's web interface with low-privilege credentials
Sending a crafted POST request to /goform/RouteStatic with a maliciously long page parameter
Overflowing the buffer to corrupt adjacent memory and potentially redirect execution flow

For detailed technical analysis of the vulnerability, refer to the GitHub README for Vulnerability and VulDB #359610.

Detection Methods for CVE-2026-7030

Indicators of Compromise

Unusual or malformed HTTP POST requests to /goform/RouteStatic with abnormally long page parameter values
Router crashes, unexpected reboots, or unresponsive web management interface
Suspicious network traffic originating from the router to unknown external destinations
Modified router configuration or unauthorized administrative accounts

Detection Strategies

Monitor web server logs for requests to /goform/RouteStatic containing oversized parameters
Implement network intrusion detection rules to flag HTTP requests with page parameters exceeding expected lengths
Deploy anomaly detection for router behavior including unexpected process crashes or memory errors
Review authentication logs for unauthorized access attempts to the router management interface

Monitoring Recommendations

Enable verbose logging on network firewalls and IDS/IPS systems monitoring traffic to the router management interface
Configure alerts for repeated failed authentication attempts followed by successful login to the router
Monitor router CPU and memory utilization for spikes that may indicate exploitation attempts
Implement network segmentation to limit exposure of router management interfaces

How to Mitigate CVE-2026-7030

Immediate Actions Required

Restrict access to the router's web management interface to trusted IP addresses only
Disable remote management if not required for operations
Change default credentials and implement strong authentication for router access
Monitor for vendor firmware updates that address this vulnerability
Consider network segmentation to isolate the vulnerable device

Patch Information

As of the last update on 2026-04-30, no official patch has been published by Tenda for this vulnerability. Users should monitor the Tenda Website for security updates and firmware releases that address CVE-2026-7030. Check the VulDB entry for updated remediation information.

Workarounds

Implement firewall rules to block external access to the /goform/RouteStatic endpoint
Use access control lists (ACLs) to restrict management interface access to specific trusted hosts
Deploy a Web Application Firewall (WAF) to filter requests with oversized parameter values
If possible, disable the static routing configuration feature if not required

bash

# Example iptables rule to restrict management interface access
# 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

# Block external access to vulnerable endpoint (if router supports custom rules)
# This should be implemented on an upstream firewall protecting the router
iptables -A FORWARD -p tcp -d <ROUTER_IP> --dport 80 -m string --string "/goform/RouteStatic" --algo bm -j DROP