CVE-2026-2530: Wavlink WL-WN579A3 Firmware RCE Vulnerability

CVE-2026-2530 Overview

CVE-2026-2530 is a command injection vulnerability in the Wavlink WL-WN579A3 wireless range extender running firmware versions up to 20210219. The flaw resides in the AddMac function within /cgi-bin/wireless.cgi, where the macAddr argument is passed to a shell context without proper sanitization. An authenticated remote attacker can inject operating system commands through this parameter. According to the disclosure, exploit details have been published, and the vendor did not respond to disclosure attempts. The weakness is classified under [CWE-74] (Improper Neutralization of Special Elements) and [CWE-77] (Command Injection).

Critical Impact

Authenticated remote attackers can execute arbitrary operating system commands on affected Wavlink WL-WN579A3 devices by injecting shell metacharacters through the macAddr parameter.

Affected Products

• Wavlink WL-WN579A3 hardware device
• Wavlink WL-WN579A3 firmware versions up to 20210219
• Deployments exposing the web management interface (/cgi-bin/wireless.cgi) to untrusted networks

Discovery Timeline

• 2026-02-16 - CVE-2026-2530 published to NVD
• 2026-04-29 - Last updated in NVD database

Technical Details for CVE-2026-2530

Vulnerability Analysis

The vulnerability exists in the AddMac function of the Common Gateway Interface (CGI) handler at /cgi-bin/wireless.cgi. This endpoint accepts a macAddr parameter intended to register MAC addresses for wireless access control. The handler concatenates the supplied value directly into a shell command without escaping or validation. Attackers who supply shell metacharacters such as ;, |, or backticks cause the device to execute attacker-controlled commands. The exploitation requires only low-privilege authenticated access to the management interface, and the attack can be performed over the network.

Root Cause

The root cause is improper neutralization of special elements used in an operating system command [CWE-77]. The AddMac function trusts client-supplied input and passes it to a shell interpreter without applying input validation, allow-listing of permissible MAC address characters, or safe argument-passing APIs. Consumer-grade embedded routers commonly use shell-based system calls in CGI scripts, which amplifies the impact of missing sanitization.

Attack Vector

The attack vector is the network-accessible web management interface of the device. An attacker authenticated to the router sends a crafted HTTP request to /cgi-bin/wireless.cgi invoking the AddMac function with a macAddr value containing shell metacharacters followed by injected commands. The injected payload runs in the context of the web server process, which on consumer routers typically runs with elevated privileges. Successful exploitation can lead to credential theft, persistent malware installation, traffic interception, and pivoting to internal network segments. Additional technical details are documented in the public GitHub IoT Vulnerability writeup and the VulDB entry #346118.

Detection Methods for CVE-2026-2530

Indicators of Compromise

• HTTP POST or GET requests to /cgi-bin/wireless.cgi containing AddMac and a macAddr parameter with non-hexadecimal or shell metacharacters such as ;, |, &, `, or $(.
• Unexpected outbound connections originating from the router's management plane shortly after web requests to wireless.cgi.
• New or modified files in writable filesystem locations on the device, such as /tmp or /var, following administrative sessions.

Detection Strategies

• Inspect web server and reverse proxy logs for macAddr values that do not match a strict MAC address pattern such as ^([0-9A-Fa-f]{2}[:-]){5}[0-9A-Fa-f]{2}$.
• Deploy network intrusion detection signatures that flag CGI requests containing shell metacharacters in MAC address fields.
• Correlate authentication events on the router's admin interface with subsequent anomalous DNS or outbound TCP activity from the device.

Monitoring Recommendations

• Forward router syslog and web access logs to a centralized analytics platform and alert on requests to wireless.cgi with suspicious payloads.
• Monitor DHCP and ARP tables for unexpected client behavior that may indicate router-level compromise.
• Track firmware version inventory across managed Wavlink devices to identify systems still running vulnerable builds.

How to Mitigate CVE-2026-2530

Immediate Actions Required

• Restrict access to the WL-WN579A3 web management interface to trusted management VLANs only and block it from WAN-facing interfaces.
• Change the default and current administrator credentials to strong unique passwords to limit who can reach the authenticated endpoint.
• Audit existing administrative sessions and access logs for evidence of exploitation against /cgi-bin/wireless.cgi.

Patch Information

No vendor patch is currently available. According to the disclosure, the vendor was contacted prior to public disclosure but did not respond. Organizations operating WL-WN579A3 devices should consider replacing affected hardware with a supported product or isolating it behind a defense-in-depth perimeter. Monitor the VulDB entry for updates on vendor remediation.

Workarounds

• Place the device behind a firewall that restricts inbound HTTP/HTTPS access to the management interface to a small set of administrative hosts.
• Disable remote administration features and any UPnP or WAN-side access on the device.
• Segment the wireless extender onto an isolated network without routes to sensitive internal assets.
• Replace end-of-support or unpatched consumer networking equipment with vendor-supported hardware that receives security updates.

# Example iptables rule to restrict management interface access to a trusted host
iptables -A INPUT -p tcp --dport 80 -s 192.0.2.10 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -s 192.0.2.10 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP