CVE-2026-3704
Published: 08 March 2026
Summary
CVE-2026-3704 is a medium-severity Injection (CWE-74) vulnerability in Wavlink Wl-Nu516U1 Firmware. Its CVSS base score is 5.1 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 47.3% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2026-3704 is a command injection vulnerability in the Wavlink NU516U1 firmware version 251208, specifically affecting the sub_405B2C function within the /cgi-bin/firewall.cgi component. This issue stems from an incomplete fix for the prior CVE-2025-10959 and is classified under CWE-74 and CWE-77. The vulnerability carries a CVSS v3.1 base score of 4.7 (AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L), indicating network accessibility with low attack complexity but requiring high privileges.
Exploitation is possible remotely by authenticated users with high privileges, such as administrative access to the device. Successful manipulation of the vulnerable function enables command injection, potentially allowing limited impacts on confidentiality, integrity, and availability, such as executing arbitrary commands within the context of the web server process.
Advisories recommend upgrading the affected component to the fixed firmware version available at https://dl.wavlink.com/firmware/RD/WINSTAR_NU516U1-WO-A-2026-02-27-2fcf6ae-mt7628-squashfs-sysupgrade.bin. The vendor was notified early, responded professionally, and promptly released the patch. Public exploit details are disclosed in GitHub repositories at https://github.com/Wlz1112/Wavlink-NU516U1-V251208-/blob/main/wavlink_DMZ.md and https://github.com/Wlz1112/Wavlink-NU516U1-V251208-/blob/main/wavlink_DMZ.md#exp, with additional coverage on VulDB at https://vuldb.com/?ctiid.349650 and https://vuldb.com/?id.349650.
The exploit has been publicly disclosed and may be used in attacks targeting unpatched devices.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-10208
Vulnerability details
A vulnerability has been found in Wavlink NU516U1 251208. This vulnerability affects the function sub_405B2C of the file /cgi-bin/firewall.cgi of the component Incomplete Fix CVE-2025-10959. The manipulation leads to command injection. It is possible to initiate the attack remotely. The…
more
exploit has been disclosed to the public and may be used. It is recommended to upgrade the affected component. The vendor was contacted early, responded in a very professional manner and quickly released a fixed version of the affected product.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Command injection in exposed network device web CGI (firewall.cgi) directly enables remote exploitation of public-facing app and arbitrary command execution on the device CLI.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly requires timely application of the vendor firmware patch that resolves the incomplete fix for CVE-2025-10959 and eliminates the command-injection flaw in firewall.cgi.
Mandates validation and sanitization of all input to sub_405B2C, blocking the unsanitized parameters that enable remote command injection.
Enforces least-privilege restrictions so that only the minimal set of administrative accounts can reach the vulnerable /cgi-bin/firewall.cgi endpoint.