CVE-2026-3274: Tenda F453 Buffer Overflow Vulnerability

CVE-2026-3274 Overview

A critical buffer overflow vulnerability has been discovered in Tenda F453 router firmware version 1.0.0.3. This security flaw affects the frmL7ProtForm function within the /goform/L7Prot endpoint of the httpd web service component. Remote attackers can exploit this vulnerability by manipulating the page argument, triggering a buffer overflow condition that could lead to arbitrary code execution or denial of service on affected devices.

Critical Impact

This network-accessible vulnerability allows remote attackers with low privileges to potentially compromise the confidentiality, integrity, and availability of affected Tenda F453 routers. A public exploit has been disclosed, increasing the risk of active exploitation.

Affected Products

• Tenda F453 Firmware version 1.0.0.3
• Tenda F453 Hardware Device

Discovery Timeline

• 2026-02-27 - CVE-2026-3274 published to NVD
• 2026-02-27 - Last updated in NVD database

Technical Details for CVE-2026-3274

Vulnerability Analysis

This buffer overflow vulnerability (CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer) occurs in the frmL7ProtForm function, which handles HTTP requests to the /goform/L7Prot endpoint in the Tenda F453's embedded web server (httpd). The vulnerability allows attackers to execute the attack remotely over the network with low attack complexity.

The flaw stems from inadequate bounds checking when processing the page parameter. When a specially crafted request with an oversized page argument is submitted to the vulnerable endpoint, the function fails to properly validate the input length before copying it into a fixed-size buffer, resulting in a classic buffer overflow condition.

Root Cause

The root cause of this vulnerability is improper input validation in the frmL7ProtForm function. The code fails to verify that user-supplied input for the page parameter does not exceed the allocated buffer size before performing memory copy operations. This allows attackers to write beyond the intended buffer boundaries, potentially corrupting adjacent memory regions including return addresses or function pointers.

Attack Vector

The attack vector is network-based, targeting the httpd web service running on Tenda F453 routers. An attacker can remotely send malicious HTTP requests to the /goform/L7Prot endpoint with a specially crafted page parameter value. The exploitation requires low privileges (authentication may be required) but no user interaction.

The vulnerability mechanism involves sending an HTTP request to the affected endpoint with an oversized page parameter value that exceeds buffer boundaries. When processed by the frmL7ProtForm function, this triggers a buffer overflow condition. Technical details and a proof-of-concept are available in the GitHub PoC Repository.

Detection Methods for CVE-2026-3274

Indicators of Compromise

• Unusual or malformed HTTP requests to /goform/L7Prot endpoint containing oversized page parameter values
• Unexpected httpd service crashes or restarts on Tenda F453 devices
• Network traffic patterns indicating exploitation attempts with large payloads targeting the web management interface
• Evidence of unauthorized access or configuration changes on affected routers

Detection Strategies

• Monitor HTTP traffic to Tenda F453 devices for requests containing abnormally long page parameters in /goform/L7Prot requests
• Implement network-based intrusion detection rules to identify buffer overflow exploitation patterns targeting the httpd service
• Deploy application-layer firewalls to inspect and filter malicious requests to the router's web interface
• Establish baseline behavior for router management traffic and alert on anomalies

Monitoring Recommendations

• Enable detailed logging on network perimeter devices monitoring traffic to and from Tenda F453 routers
• Configure SIEM alerts for httpd service crashes or unexpected restarts on affected devices
• Implement network segmentation to isolate router management interfaces from untrusted networks
• Regularly audit access logs for the router's web management interface

How to Mitigate CVE-2026-3274

Immediate Actions Required

• Restrict network access to the Tenda F453 web management interface to trusted IP addresses only
• Disable remote management if not required, limiting access to local network only
• Implement firewall rules to block external access to the /goform/L7Prot endpoint
• Monitor for any suspicious activity targeting the affected device

Patch Information

At the time of publication, no official patch information is available from Tenda for this vulnerability. Organizations should monitor the Tenda Official Website for firmware updates. Additional vulnerability tracking information is available at VulDB #347998.

Workarounds

• Disable the web management interface entirely if not operationally required
• Use network access control lists (ACLs) to restrict management interface access to specific trusted administrator IPs
• Place the router behind a firewall that can filter and inspect HTTP traffic for malicious patterns
• Consider replacing affected devices with alternative products if patches are not made available in a timely manner

# Example network ACL configuration to restrict management access
# Apply on upstream firewall or router
# Deny external access to Tenda F453 management interface
iptables -A FORWARD -d <TENDA_F453_IP> -p tcp --dport 80 -j DROP
iptables -A FORWARD -d <TENDA_F453_IP> -p tcp --dport 443 -j DROP

# Allow only trusted management IP
iptables -I FORWARD -s <TRUSTED_ADMIN_IP> -d <TENDA_F453_IP> -p tcp --dport 80 -j ACCEPT