CVE-2026-2526: Wavlink WL-WN579A3 Firmware RCE Vulnerability

CVE-2026-2526 Overview

CVE-2026-2526 is a command injection vulnerability affecting Wavlink WL-WN579A3 wireless devices running firmware versions up to 20210219. The flaw resides in the multi_ssid function within /cgi-bin/wireless.cgi, where the SSID2G2 argument is processed without proper sanitization. An authenticated remote attacker can manipulate this parameter to inject arbitrary operating system commands. The exploit has been disclosed publicly. According to the disclosure, the vendor was contacted but did not respond. This vulnerability maps to [CWE-77] Improper Neutralization of Special Elements used in a Command and [CWE-74] Improper Neutralization of Special Elements in Output.

Critical Impact
Authenticated attackers can execute arbitrary operating system commands on affected Wavlink WL-WN579A3 devices through the SSID2G2 parameter, potentially leading to full device compromise.

Affected Products

Wavlink WL-WN579A3 firmware versions up to 20210219
Wavlink WL-WN579A3 hardware device
CGI handler /cgi-bin/wireless.cgi (multi_ssid function)

Discovery Timeline

2026-02-16 - CVE-2026-2526 published to NVD
2026-04-29 - Last updated in NVD database

Technical Details for CVE-2026-2526

Vulnerability Analysis

The vulnerability resides in the multi_ssid function inside the /cgi-bin/wireless.cgi script on Wavlink WL-WN579A3 devices. The function processes user-supplied wireless configuration parameters, including the SSID2G2 argument used to configure a secondary 2.4 GHz SSID. The handler passes this parameter into a shell context without validating or escaping shell metacharacters. As a result, attacker-controlled input is interpreted as part of an OS command rather than as data.

Because the affected endpoint is exposed via the device's HTTP management interface, exploitation occurs over the network. The attacker must possess low-privilege credentials on the web management interface to reach the vulnerable handler. Successful exploitation yields command execution in the context of the web server process, which on consumer wireless devices typically runs with elevated privileges.

Root Cause

The root cause is missing input neutralization in the multi_ssid handler. The SSID2G2 parameter is concatenated into a system command string and dispatched to a shell interpreter. Shell metacharacters such as ;, |, &, and backticks are not filtered, allowing arbitrary command chaining. This pattern is characteristic of [CWE-77] and is common in embedded router firmware that wraps CLI utilities behind CGI scripts.

Attack Vector

The attack is conducted remotely over the HTTP management interface of the device. An attacker who has authenticated to the web UI submits a crafted request to /cgi-bin/wireless.cgi invoking the multi_ssid action with a malicious SSID2G2 value. The injected payload executes when the firmware applies the wireless configuration. Technical proof-of-concept details are documented in the GitHub Multi SSID Vulnerability Report and the VulDB entry for #346114.

No verified code examples are available. Refer to the linked advisories for parameter-level technical details.

Detection Methods for CVE-2026-2526

Indicators of Compromise

HTTP POST requests to /cgi-bin/wireless.cgi containing shell metacharacters (;, |, &, `, $() inside the SSID2G2 parameter.
Unexpected child processes spawned by the device web server, such as sh, wget, curl, nc, or telnetd.
New listening TCP ports or outbound connections originating from the router to attacker-controlled infrastructure.
Modifications to wireless configuration files or /etc/ contents that do not correlate with administrator activity.

Detection Strategies

Inspect HTTP traffic to the device management interface for non-printable or shell-metacharacter content in SSID-related fields.
Deploy network intrusion detection rules that flag CGI requests to wireless.cgi containing command-chaining syntax in form parameters.
Correlate authentication events on the device with subsequent configuration-change requests to identify abuse of low-privileged accounts.

Monitoring Recommendations

Restrict and log all access to the device's HTTP and HTTPS management interfaces, especially from non-administrative network segments.
Monitor DNS and egress traffic from IoT VLANs for anomalous destinations indicative of post-exploitation tooling.
Maintain an inventory of Wavlink devices and firmware versions, and alert when devices at or below firmware 20210219 are detected.

How to Mitigate CVE-2026-2526

Immediate Actions Required

Remove the device's management interface from any untrusted or internet-facing network. Bind it to a dedicated management VLAN.
Rotate all administrative and low-privileged credentials on affected Wavlink WL-WN579A3 units and enforce strong, unique passwords.
Treat any device exhibiting indicators of compromise as fully compromised, factory-reset it, and reconfigure from a known-good baseline.
Evaluate replacement of the device, since the vendor did not respond to disclosure attempts.

Patch Information

No vendor patch is currently available. The disclosure notes the vendor was contacted but did not respond. Monitor the Wavlink support site and the VulDB advisory for any future firmware updates.

Workarounds

Disable remote administration features and block WAN access to the management interface using upstream firewall rules.
Restrict access to /cgi-bin/wireless.cgi via an upstream reverse proxy or access control list, permitting only trusted administrative hosts.
Limit the number of accounts with access to the web UI and avoid sharing low-privileged credentials.
Where feasible, replace affected hardware with an actively maintained device that receives security updates.

bash

# Example firewall rule restricting management interface access to a trusted host
# Replace 192.0.2.10 with the administrative workstation IP and 192.168.1.1 with the device IP
iptables -A FORWARD -p tcp -d 192.168.1.1 --dport 80 -s 192.0.2.10 -j ACCEPT
iptables -A FORWARD -p tcp -d 192.168.1.1 --dport 80 -j DROP
iptables -A FORWARD -p tcp -d 192.168.1.1 --dport 443 -s 192.0.2.10 -j ACCEPT
iptables -A FORWARD -p tcp -d 192.168.1.1 --dport 443 -j DROP