CVE-2026-3376:

Security Advisory: Critical Buffer Overflow Vulnerability in Tenda F453 Router Firmware

Overview

A critical security vulnerability has been identified in the Tenda F453 router, firmware version 1.0.0.3. The flaw resides in a specific function that handles MAC address filtering, a common feature used to restrict network access. Attackers can exploit this weakness remotely without requiring prior access to the device or network.

Vulnerability Details

The vulnerability is a buffer overflow in the fromSafeMacFilter function within the /goform/SafeMacFilter module. In simple terms, this function does not properly validate or limit the amount of data it receives. By sending a specially crafted, oversized request to the “page” argument, an attacker can overwhelm the router’s memory. This corruption can cause the device to crash or, more critically, allow the attacker to execute their own malicious code on the router itself.

Impact

Given the high CVSS score of 8.8, the potential impact is severe:

• Remote Code Execution (RCE): An unauthenticated attacker on your network could potentially take full control of the router.
• Denial of Service (DoS): The router could be forced to reboot or become unresponsive, disrupting internet connectivity for all connected devices.
• Network Compromise: With control of the router, an attacker could redirect traffic, intercept sensitive data (like passwords and banking details), or use your network to launch further attacks.
• Public Exploit: The exploit technique has been publicly disclosed, increasing the likelihood of active attacks.

Affected Products

• Device: Tenda F453 Wireless Router
• Firmware Version: 1.0.0.3
• Other firmware versions may also be affected and should be verified.

Remediation and Mitigation

Immediate action is required to protect your network.

Primary Action - Update Firmware:

1. Check for Updates: Log in to your Tenda F453 router’s web administration panel.
2. Navigate to the system or firmware upgrade section.
3. Check for and install the latest official firmware version provided by Tenda. If version 1.0.0.3 is the latest, contact Tenda support directly to inquire about a security patch.

If No Patch is Available - Apply Mitigations:

• Disable Remote Management: Ensure the router’s administration interface is not accessible from the internet (WAN). It should only be accessible from your local network (LAN).
• Segment Your Network: Place sensitive devices on a separate network segment or VLAN if possible.
• Monitor for Anomalies: Watch for unexpected router reboots, slow performance, or unfamiliar devices on your network.

General Best Practice:

• Change the router’s default admin password to a strong, unique passphrase.
• Regularly check the manufacturer’s website for security advisories and firmware updates for all network devices.

You should treat this vulnerability with high priority due to its remote exploitability and the critical role of the router as your network’s primary defense.