CVE-2026-2527 Overview
CVE-2026-2527 is a command injection vulnerability affecting Wavlink WL-WN579A3 wireless devices through firmware version 20210219. The flaw exists in the /cgi-bin/login.cgi endpoint, where the key argument is passed to a shell context without proper sanitization. Authenticated remote attackers can manipulate this parameter to execute operating system commands on the device. A public proof of concept has been disclosed, increasing the likelihood of opportunistic exploitation against exposed devices. The vendor was contacted prior to disclosure but did not respond, and no patch is currently available. The vulnerability is categorized under [CWE-74] Improper Neutralization of Special Elements and [CWE-77] Command Injection.
Critical Impact
Remote attackers with low-privilege access can inject operating system commands through the key parameter of login.cgi, achieving code execution on affected Wavlink routers.
Affected Products
- Wavlink WL-WN579A3 hardware
- Wavlink WL-WN579A3 firmware up to version 20210219
- Networks exposing the device web management interface
Discovery Timeline
- 2026-02-16 - CVE-2026-2527 published to the National Vulnerability Database
- 2026-04-29 - Last updated in NVD database
Technical Details for CVE-2026-2527
Vulnerability Analysis
The vulnerability resides in the login handler implemented in /cgi-bin/login.cgi on the Wavlink WL-WN579A3 web administration interface. The endpoint accepts a key argument that is incorporated into a command executed by the underlying shell. Because the value is not sanitized or escaped, shell metacharacters supplied by an attacker are interpreted as command separators or substitutions. This allows arbitrary commands to run in the context of the web server process, which on consumer router firmware typically operates with elevated privileges. Successful exploitation can lead to configuration changes, credential theft, traffic interception, and persistent device compromise that enables pivoting into the local network.
Root Cause
The root cause is improper neutralization of special elements used in an operating system command [CWE-77]. The login.cgi handler concatenates the attacker-controlled key parameter directly into a shell invocation without input validation, allowlisting, or use of safe APIs that separate command arguments from interpreter metacharacters.
Attack Vector
The attack is network-reachable and requires low privileges, as indicated by the CVSS vector component PR:L. An attacker submits an HTTP request to /cgi-bin/login.cgi containing a crafted key parameter with embedded shell metacharacters such as backticks, semicolons, or command substitution sequences. The injected payload executes when the CGI handler invokes the shell. Public exploitation details are available in the disclosed proof of concept, which lowers the skill barrier for attackers targeting exposed devices.
No verified exploit code is reproduced here. Technical details and the disclosed proof of concept are available at the GitHub Proof of Concept and VulDB entry #346115.
Detection Methods for CVE-2026-2527
Indicators of Compromise
- HTTP POST or GET requests to /cgi-bin/login.cgi containing shell metacharacters in the key parameter, including ;, |, &, backticks, or $() sequences.
- Unexpected outbound connections from the router to attacker-controlled infrastructure shortly after requests to the login endpoint.
- New or modified files in firmware writable locations such as /tmp, /var, or NVRAM-backed configuration stores.
- Unauthorized changes to DNS, routing, or firewall configuration on the device.
Detection Strategies
- Inspect web access logs and network captures for requests to /cgi-bin/login.cgi containing non-printable or shell-special characters in URL or body parameters.
- Apply intrusion detection signatures that match command injection patterns targeting the key parameter on the affected URI.
- Baseline expected administrative traffic to router management interfaces and alert on anomalous source addresses or request volumes.
Monitoring Recommendations
- Forward network telemetry from router-adjacent network sensors into a centralized analytics platform for correlation against known IoT exploitation patterns.
- Monitor for unexpected DNS queries originating from network gateways, which can indicate post-exploitation command and control.
- Track configuration drift on managed network devices and flag firmware versions that have reached end-of-support or lack vendor responses to disclosure.
How to Mitigate CVE-2026-2527
Immediate Actions Required
- Restrict access to the WL-WN579A3 web administration interface to trusted management VLANs and block exposure to the internet.
- Disable remote administration features on the device and require VPN access for any management activity.
- Rotate administrative credentials and review device configuration for unauthorized changes.
- Plan replacement of affected hardware given the absence of a vendor response and patch.
Patch Information
No vendor patch is currently available. The vendor was contacted prior to public disclosure but did not respond. Organizations operating Wavlink WL-WN579A3 devices through firmware 20210219 should treat the device as unsupported for security purposes and evaluate replacement with a vendor-maintained alternative. Monitor the VulDB CTI entry for updates if Wavlink later releases a fix.
Workarounds
- Place affected devices behind a network segment with strict ingress filtering and deny external access to TCP ports serving the web interface.
- Apply ACLs on upstream switches or firewalls to limit login.cgi access to a small set of trusted administrative IP addresses.
- Where possible, replace the device with an actively supported model that receives security updates.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
