CVE-2026-0408: NETGEAR WiFi Extender Path Traversal Flaw

CVE-2026-0408 Overview

A path traversal vulnerability has been identified in NETGEAR WiFi range extenders that allows an attacker with LAN authentication to access the router's IP and review the contents of the dynamically generated webproc file. This file records the username and password submitted to the router GUI, potentially exposing administrative credentials to unauthorized parties on the local network.

Critical Impact

Authenticated attackers on the local network can extract administrator credentials from the webproc file through path traversal, enabling complete device takeover and potential pivot attacks on the broader network infrastructure.

Affected Products

• NETGEAR EX2800 WiFi Range Extender
• NETGEAR EX3110 WiFi Range Extender
• NETGEAR EX5000 WiFi Range Extender
• NETGEAR EX6110 WiFi Range Extender

Discovery Timeline

• 2026-01-13 - CVE-2026-0408 published to NVD
• 2026-01-13 - Last updated in NVD database

Technical Details for CVE-2026-0408

Vulnerability Analysis

This vulnerability stems from improper authentication controls (CWE-287) combined with insufficient path validation in the web management interface of affected NETGEAR range extenders. The attack requires adjacent network access and low-privilege authentication, meaning an attacker must first be connected to the same LAN segment as the target device.

The core issue lies in how the device's web server handles file path requests. When authenticated users interact with the router GUI, the device dynamically generates a webproc file that stores submitted credentials in plaintext or a recoverable format. The path traversal flaw allows authenticated users to navigate outside the intended web root directory and access this sensitive file.

Root Cause

The vulnerability is rooted in improper authentication mechanisms (CWE-287) where the web interface fails to properly restrict access to internal system files. The webproc file, which should be protected from direct access, can be reached through directory traversal sequences. This represents a design flaw where credential storage intersects with inadequate access controls on the file system level.

Attack Vector

The attack is executed from an adjacent network position, requiring the attacker to have established LAN connectivity and possess valid low-level authentication credentials. Once authenticated, the attacker crafts HTTP requests containing path traversal sequences (such as ../ patterns) to escape the web root directory and access the webproc file.

The dynamically generated nature of the webproc file means it contains recently submitted credentials, potentially including the administrator username and password. Successful exploitation grants the attacker full administrative access to the range extender, which could be leveraged to modify DNS settings, intercept traffic, or use the device as a pivot point for further network attacks.

Detection Methods for CVE-2026-0408

Indicators of Compromise

• HTTP requests to the router management interface containing path traversal sequences (../, ..%2f, or encoded variants)
• Unusual access patterns to the webproc file or other internal system files
• Authentication logs showing access attempts followed by requests to non-standard file paths
• Unexpected changes to router configuration after credential exposure

Detection Strategies

• Monitor web server access logs on network devices for path traversal patterns in URI requests
• Implement network-based intrusion detection rules to identify traversal sequences targeting NETGEAR management interfaces
• Review SIEM alerts for authentication events followed by suspicious file access attempts on embedded device management portals
• Deploy network traffic analysis to detect anomalous requests to range extender management interfaces

Monitoring Recommendations

• Enable comprehensive logging on network management interfaces where available
• Configure alerting for multiple failed authentication attempts followed by successful logins from the same source
• Establish baseline network behavior to identify unusual traffic patterns targeting infrastructure devices
• Regularly audit access logs for evidence of path traversal exploitation attempts

How to Mitigate CVE-2026-0408

Immediate Actions Required

• Check the NETGEAR Security Advisory January 2026 for the latest firmware updates for affected devices
• Update firmware on all affected NETGEAR range extenders (EX2800, EX3110, EX5000, EX6110) to the latest available version
• Change administrative credentials immediately, especially if the device may have been exposed
• Restrict access to the management interface by limiting which devices can connect to the configuration portal
• Review network segmentation to ensure range extenders are not directly accessible from untrusted network segments

Patch Information

NETGEAR has released security updates addressing this vulnerability. Administrators should visit the official NETGEAR support pages for their specific device models to download the latest firmware:

• NETGEAR EX2800 Support Page
• NETGEAR EX3110 Support Page
• NETGEAR EX5000 Support Page
• NETGEAR EX6110 Support Page

Workarounds

• Disable remote management features if not required for operations
• Implement network segmentation to isolate range extenders from potentially compromised hosts
• Use strong, unique administrative credentials that are not reused across devices
• Consider disabling the web management interface and using alternative configuration methods if available
• Restrict physical and network access to the management interface to trusted administrators only