CVE-2026-3275: Tenda F453 Buffer Overflow Vulnerability

CVE-2026-3275 Overview

A buffer overflow vulnerability has been identified in Tenda F453 router firmware version 1.0.0.3. This affects the function fromAddressNat of the file /goform/addressNat within the httpd component. By manipulating the entrys argument, an attacker can trigger a buffer overflow condition that may lead to arbitrary code execution or denial of service. The attack can be performed remotely over the network, and the exploit has been made available to the public, increasing the risk of active exploitation.

Critical Impact

Remote attackers can exploit this buffer overflow vulnerability in Tenda F453 routers to potentially execute arbitrary code, compromise network infrastructure, or cause denial of service conditions on affected devices.

Affected Products

• Tenda F453 Firmware version 1.0.0.3
• Tenda F453 Hardware
• Tenda F453 Router httpd Component

Discovery Timeline

• 2026-02-27 - CVE CVE-2026-3275 published to NVD
• 2026-02-27 - Last updated in NVD database

Technical Details for CVE-2026-3275

Vulnerability Analysis

This vulnerability is classified as CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The fromAddressNat function in the Tenda F453 httpd web server component fails to properly validate the length of data passed through the entrys parameter before copying it into a fixed-size buffer. This lack of bounds checking allows an attacker to submit a specially crafted request containing overly long input that overwrites adjacent memory regions.

The vulnerability is remotely exploitable over the network without requiring user interaction. An attacker with low-level authentication privileges can send malicious HTTP requests to the /goform/addressNat endpoint to trigger the buffer overflow. Successful exploitation could allow an attacker to overwrite critical memory structures, potentially leading to arbitrary code execution with the privileges of the httpd process, which typically runs as root on embedded devices like routers.

Root Cause

The root cause of this vulnerability lies in improper input validation within the fromAddressNat function. The function processes user-supplied data from the entrys argument without implementing adequate length checks or boundary validation before performing memory copy operations. This is a common vulnerability pattern in embedded device firmware where memory-safe programming practices may not be consistently applied due to resource constraints or legacy code.

Attack Vector

The attack vector is network-based, allowing remote exploitation. An attacker can craft malicious HTTP POST requests targeting the /goform/addressNat endpoint on the Tenda F453 router's web management interface. By including an excessively long entrys parameter value, the attacker can overflow the target buffer and corrupt adjacent memory.

The vulnerability allows attackers to potentially achieve remote code execution on the router, which could result in complete device compromise, network traffic interception, router configuration modification, or use of the compromised device as a pivot point for further network attacks.

For detailed technical analysis and proof-of-concept information, refer to the GitHub Vulnerability Repository.

Detection Methods for CVE-2026-3275

Indicators of Compromise

• Unusual HTTP POST requests to /goform/addressNat with abnormally large entrys parameter values
• Unexpected crashes or restarts of the httpd service on Tenda F453 devices
• Anomalous network traffic patterns originating from or destined to Tenda routers on management ports
• Unauthorized configuration changes on affected router devices

Detection Strategies

• Deploy network intrusion detection systems (NIDS) with signatures to detect malformed HTTP requests to Tenda router endpoints
• Monitor web server logs on Tenda devices for requests with oversized parameter values targeting /goform/addressNat
• Implement web application firewalls (WAF) to filter requests with excessively long parameter values
• Use SentinelOne Singularity to monitor for anomalous process behavior on network infrastructure devices

Monitoring Recommendations

• Enable logging on all Tenda router web management interfaces and forward logs to a centralized SIEM
• Set up alerts for HTTP requests exceeding normal parameter length thresholds to router endpoints
• Regularly audit network device configurations for unauthorized modifications
• Monitor for unexpected outbound connections from router devices that may indicate compromise

How to Mitigate CVE-2026-3275

Immediate Actions Required

• Restrict access to the Tenda F453 web management interface to trusted IP addresses only
• Disable remote management access if not required for operational purposes
• Implement network segmentation to isolate IoT and network infrastructure devices
• Deploy firewall rules to block external access to router management ports

Patch Information

At the time of publication, no official patch has been released by Tenda for this vulnerability. Organizations should monitor the Tenda Official Site for firmware updates addressing CVE-2026-3275. Contact Tenda support directly for guidance on remediation options.

Additional technical details and vulnerability tracking information can be found at:

• VulDB Entry #347999
• VulDB CTI ID #347999

Workarounds

• Place Tenda F453 routers behind a firewall that restricts access to the management interface
• Disable the web management interface entirely if not operationally required
• Use VPN access for remote management rather than exposing the web interface directly
• Consider replacing affected devices with alternatives from vendors with better security response practices

# Example: Restrict access to router management interface via upstream firewall
# Block external access to common router management ports
iptables -A INPUT -p tcp --dport 80 -s ! 192.168.1.0/24 -j DROP
iptables -A INPUT -p tcp --dport 443 -s ! 192.168.1.0/24 -j DROP