CVE-2026-7078: Tenda F456 Buffer Overflow Vulnerability

CVE-2026-7078 Overview

A buffer overflow vulnerability has been identified in the Tenda F456 wireless router running firmware version 1.0.0.5. The vulnerability exists within the fromSetIpBind function located in the /goform/SetIpBind endpoint of the httpd component. Improper handling of the page argument allows an attacker to trigger a buffer overflow condition. This vulnerability can be exploited remotely over the network by authenticated users, potentially leading to arbitrary code execution or denial of service on affected devices.

Critical Impact

Remote exploitation of this buffer overflow vulnerability could allow attackers to execute arbitrary code, crash the device, or gain unauthorized control over the router, compromising network security.

Affected Products

• Tenda F456 (Hardware)
• Tenda F456 Firmware version 1.0.0.5

Discovery Timeline

• 2026-04-27 - CVE-2026-7078 published to NVD
• 2026-04-30 - Last updated in NVD database

Technical Details for CVE-2026-7078

Vulnerability Analysis

This vulnerability is classified as CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The fromSetIpBind function in the Tenda F456 router's httpd service fails to properly validate the length of user-supplied input for the page parameter before copying it into a fixed-size buffer. When an attacker supplies an overly long string, the data overflows the allocated buffer space, potentially overwriting adjacent memory regions including return addresses or function pointers.

The network-accessible nature of this flaw means attackers can craft malicious HTTP requests targeting the /goform/SetIpBind endpoint to trigger the overflow condition. Successful exploitation requires low-privilege authentication but no user interaction, making it particularly dangerous in scenarios where default or weak credentials are in use.

Root Cause

The root cause of this vulnerability is insufficient bounds checking on the page argument within the fromSetIpBind function. The httpd web service does not validate the length of incoming data before performing memory copy operations, resulting in a classic stack-based or heap-based buffer overflow depending on the memory allocation strategy used by the firmware.

Attack Vector

The attack is network-based and targets the httpd web interface of the Tenda F456 router. An authenticated attacker can send a specially crafted HTTP POST request to the /goform/SetIpBind endpoint with a malformed page parameter containing excessive data. The overflow corrupts memory structures, potentially allowing code execution in the context of the httpd process.

The vulnerability has been publicly disclosed with a proof-of-concept available in the GitHub PoC Repository. This increases the risk of exploitation in the wild as technical details are accessible to potential attackers.

Detection Methods for CVE-2026-7078

Indicators of Compromise

• Unusual HTTP POST requests to /goform/SetIpBind with abnormally large page parameter values
• Router crashes or unexpected reboots following web interface access
• Anomalous outbound network connections originating from the router
• Modified router configurations or unauthorized administrative accounts

Detection Strategies

• Monitor network traffic for HTTP requests to /goform/SetIpBind endpoints containing oversized parameters
• Implement intrusion detection rules to flag requests with page parameter values exceeding expected lengths
• Deploy network behavior analysis to detect router communication anomalies
• Review httpd service logs for crash events or access control violations

Monitoring Recommendations

• Enable logging on network segments containing Tenda F456 devices
• Configure SIEM alerts for repeated failed authentication attempts followed by successful access
• Monitor for firmware modification attempts or configuration changes
• Establish baseline traffic patterns for router management interfaces to identify deviations

How to Mitigate CVE-2026-7078

Immediate Actions Required

• Restrict network access to the router's web management interface to trusted IP addresses only
• Change default credentials and implement strong authentication for administrative access
• Disable remote management if not required for operations
• Place affected devices behind a firewall with strict ingress filtering
• Monitor for vendor firmware updates addressing this vulnerability

Patch Information

At the time of publication, no official patch has been released by Tenda for this vulnerability. Users should monitor the Tenda Security Page for firmware updates. Additional technical details can be found at VulDB #359653.

Workarounds

• Disable the web management interface entirely if not required
• Implement network segmentation to isolate vulnerable devices from untrusted networks
• Use access control lists (ACLs) to limit management interface access to specific administrator IPs
• Consider replacing affected devices with alternative hardware until a patch is available
• Enable VPN access for remote administration rather than exposing the web interface directly

# Example: Restrict access to management interface via iptables on upstream firewall
iptables -A FORWARD -d <ROUTER_IP> -p tcp --dport 80 -s <ADMIN_IP> -j ACCEPT
iptables -A FORWARD -d <ROUTER_IP> -p tcp --dport 80 -j DROP