CVE-2026-4164: Wavlink WL-WN578W2 RCE Vulnerability

CVE-2026-4164 Overview

CVE-2026-4164 is a command injection vulnerability in the Wavlink WL-WN578W2 wireless range extender running firmware version 221110. The flaw exists in the Delete_Mac_list, SetName, and GuestWifi functions of the /cgi-bin/wireless.cgi script. Attackers can send a crafted POST request to inject and execute arbitrary operating system commands on the device. The attack requires no authentication, no user interaction, and can be launched remotely over the network. A public exploit has been released, increasing the likelihood of opportunistic attacks against exposed devices. The vulnerability maps to [CWE-74] Improper Neutralization of Special Elements in Output Used by a Downstream Component.

Critical Impact
Unauthenticated remote attackers can execute arbitrary commands on affected Wavlink WL-WN578W2 devices, leading to full device compromise and a foothold inside the connected network.

Affected Products

Wavlink WL-WN578W2 firmware version 221110
/cgi-bin/wireless.cgi POST Request Handler component
Functions Delete_Mac_list, SetName, and GuestWifi

Discovery Timeline

2026-03-16 - CVE-2026-4164 published to NVD
2026-04-22 - Last updated in NVD database

Technical Details for CVE-2026-4164

Vulnerability Analysis

The Wavlink WL-WN578W2 exposes a web management interface that routes wireless configuration requests through the /cgi-bin/wireless.cgi binary. Three handler functions, Delete_Mac_list, SetName, and GuestWifi, accept attacker-controlled parameters from POST requests and pass them into shell command execution without proper neutralization. An attacker reaching the device on its HTTP interface can append shell metacharacters to these parameters and have the embedded Linux system execute them under the privileges of the web server, which typically runs as root on this class of consumer device. Successful exploitation yields arbitrary command execution, persistence on the firmware, traffic interception, and lateral movement into the network the extender bridges. The vendor has published an updated firmware image, and the public availability of proof-of-concept material makes patching urgent.

Root Cause

The root cause is improper neutralization of special elements in the input passed to a downstream shell interpreter [CWE-74]. The affected CGI handlers concatenate user-supplied POST parameters into command strings invoked through a system shell, allowing characters such as ;, |, &, and backticks to terminate the intended command and inject new ones.

Attack Vector

Exploitation occurs over the network against the device's HTTP management interface. The attacker sends a POST request to /cgi-bin/wireless.cgi invoking one of the vulnerable functions with a parameter value containing shell metacharacters and an attacker-chosen payload. No credentials and no user interaction are required. The vulnerability is described in the public write-ups at GitHub VulDB README 1 and GitHub VulDB README 2, and tracked in VulDB #351071.

Detection Methods for CVE-2026-4164

Indicators of Compromise

POST requests to /cgi-bin/wireless.cgi containing shell metacharacters such as ;, |, &, $(, or backticks in the Delete_Mac_list, SetName, or GuestWifi parameters.
Outbound connections from the Wavlink device to unfamiliar IP addresses or download of binaries via wget, curl, or tftp shortly after a POST to wireless.cgi.
New or unexpected processes running on the device, including reverse shells listening on non-standard ports.

Detection Strategies

Inspect HTTP request bodies destined for the extender's management interface for shell metacharacters in wireless.cgi parameters.
Correlate web request logs with subsequent egress traffic from the device to detect command-and-control callbacks.
Hunt for the specific function names Delete_Mac_list, SetName, and GuestWifi in proxy and IDS logs to identify probing activity.

Monitoring Recommendations

Place affected Wavlink devices on a monitored network segment and alert on any inbound connection to TCP/80 or TCP/443 from outside the management network.
Baseline normal outbound traffic from the extender and alert on deviations such as connections to public IPs over uncommon ports.
Forward router and IDS telemetry to a central analytics platform to correlate exploit attempts across devices.

How to Mitigate CVE-2026-4164

Immediate Actions Required

Apply the vendor firmware update available from Wavlink Firmware Update to all WL-WN578W2 devices running firmware 221110.
Restrict access to the device's web management interface so it is reachable only from a trusted administrative subnet.
Disable remote or WAN-side administration if it has been enabled.
Audit the device for signs of prior compromise, including unexpected accounts, scripts, or outbound connections, before and after upgrading.

Patch Information

Wavlink has released firmware image WINSTAR_WN578W2-A-2026-03-10-94f93d4-WO-mt7628-squashfs-sysupgrade.bin to address the command injection. Download and verify the image from the official vendor location at Wavlink Firmware Update and flash it through the device's standard upgrade procedure. After upgrade, reset the device to factory defaults and reconfigure to ensure no attacker-implanted configuration persists.

Workarounds

Block inbound HTTP and HTTPS access to the extender from untrusted networks using upstream firewall rules.
Place the device on an isolated VLAN with no route to sensitive internal systems until firmware can be applied.
Replace end-of-support or unmanaged Wavlink devices with hardware that receives regular security updates if patching is not feasible.

bash

# Example firewall rule to restrict management access to the extender
# Replace 192.0.2.10 with the device IP and 10.0.0.0/24 with your admin subnet
iptables -A FORWARD -p tcp -d 192.0.2.10 --dport 80  -s 10.0.0.0/24 -j ACCEPT
iptables -A FORWARD -p tcp -d 192.0.2.10 --dport 443 -s 10.0.0.0/24 -j ACCEPT
iptables -A FORWARD -p tcp -d 192.0.2.10 --dport 80  -j DROP
iptables -A FORWARD -p tcp -d 192.0.2.10 --dport 443 -j DROP