Wavlink WL-WN530H4 OS Command Injection Vulnerability

A critical OS command injection vulnerability, tracked as CVE-2026-6483, has been identified in Wavlink WL-WN530H4 routers running firmware version 20220721. The flaw resides within the /cgi-bin/internet.cgi file, specifically affecting the strcat/snprintf function. Successful exploitation enables remote attackers to execute arbitrary OS commands on the affected device. The vulnerability is triggered by manipulating input to the vulnerable function. A public exploit is available, increasing the risk of widespread exploitation. Users are advised to upgrade to version 2026.04.16 to mitigate the risk. This vulnerability poses a significant threat due to the potential for complete system compromise, potentially leading to data exfiltration, device hijacking, or denial-of-service attacks.

Attack Chain

1. The attacker identifies a Wavlink WL-WN530H4 router running firmware version 20220721.
2. The attacker crafts a malicious HTTP request targeting the /cgi-bin/internet.cgi endpoint.
3. The crafted request includes a payload designed to exploit the strcat/snprintf function.
4. The vulnerable strcat/snprintf function fails to properly sanitize the attacker-controlled input.
5. The unsanitized input is passed to a system call, resulting in OS command injection.
6. The attacker executes arbitrary OS commands with the privileges of the web server process.
7. The attacker can leverage the compromised system to perform actions such as modifying router configuration, installing malware, or pivoting to other network devices.
8. The attacker gains persistent access and control over the router.

Impact

Successful exploitation of this vulnerability allows a remote attacker to execute arbitrary OS commands on the affected Wavlink router. This can lead to a complete compromise of the device, allowing the attacker to modify router settings, intercept network traffic, or use the router as a launchpad for further attacks within the network. The lack of specifics regarding victimology suggests a wide potential impact affecting numerous users and potentially small businesses relying on these routers.

Recommendation

• Upgrade the Wavlink WL-WN530H4 router to firmware version 2026.04.16 to patch CVE-2026-6483.
• Deploy the Sigma rule “Detect Wavlink Command Injection Attempt” to monitor for malicious requests targeting /cgi-bin/internet.cgi.
• Monitor web server logs for suspicious activity and unauthorized access attempts following exploitation of CVE-2026-6483.