CVE-2026-3380: Buffer Overflow — Patch Guide

Vendor-confirmed - CVE-2026-3380 is a high severity buffer overflow in Tenda F453 router firmware version 1.0.0.3 that grants unauthenticated remote code execution. Apply the patched firmware update as soon as available.

Security Advisory: Critical Buffer Overflow in Tenda F453 Router

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 web management function that improperly handles input data. An attacker can send a specially crafted network request to the router, triggering a buffer overflow - a condition where excess data overruns the memory space allocated for it. This vulnerability is remotely exploitable, meaning an attacker does not need physical or local network access to the device to launch an attack. Publicly available exploit code increases the urgency for remediation.

Vulnerability Details

The vulnerability exists in the frmL7ImForm function within the /goform/L7Im component of the router’s web management interface. This function is responsible for processing certain configuration requests. By manipulating the “page” argument in a request with an overly long string of data, an attacker can corrupt the router’s memory. This corruption can destabilize the system, causing crashes, or, more critically, allow the attacker to execute arbitrary code on the device.

Potential Impact

If successfully exploited, this high-severity vulnerability could allow an unauthenticated remote attacker to:

• Take Full Control: Execute malicious code with the same privileges as the router’s operating system, potentially leading to a complete compromise.
• Disrupt Network Services: Crash the router’s software, causing a denial-of-service (DoS) and internet outage for all connected users.
• Enable Further Attacks: Use the compromised router as a foothold to launch attacks against other devices on the internal network, such as computers, phones, or smart home devices.
• Intercept Traffic: Potentially monitor, redirect, or modify internet traffic passing through the router.

Remediation and Mitigation

Immediate action is required to protect affected networks.

Primary Solution - Firmware Update:

1. Check for Updates: Log in to your Tenda F453 router’s web administration panel.
2. Navigate to the “System Tools” or “Advanced” section and look for a “Firmware Upgrade” option.
3. Check the Tenda website for a firmware version newer than 1.0.0.3 that addresses this CVE. If an update is available, apply it immediately. As of this advisory, a fixed version may not yet be released.

Interim Mitigations:

• Disable Remote Management: Ensure the router’s “Remote Management” feature is turned OFF. This prevents the vulnerable interface from being accessed directly from the internet. The feature is typically found in the “Security” or “Administration” settings.
• Network Segmentation: If possible, place the router behind a firewall that restricts inbound WAN access to its administrative ports (commonly TCP 80 and 443).
• Monitor for Updates: Regularly check the official Tenda support site for a security patch or updated firmware and apply it as soon as it is released.

If no patch becomes available, consider replacing the router with a model from a vendor that provides active security support.