CVE-2026-3703 Wavlink NU516U1 login.cgi sub_401A10 out-of-bounds write

Critical 9.3 Published 8 Mar 2026 Updated 10 Mar 2026

Remote attackers can trigger an out-of-bounds write in the login CGI script, potentially leading to code execution on Wavlink NU516U1 routers.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-3703?

CVE-2026-3703 is a critical memory corruption vulnerability in Wavlink NU516U1, published on 8 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A flaw has been found in Wavlink NU516U1 251208. This affects the function sub_401A10 of the file /cgi-bin/login.cgi. Executing a manipulation of the argument ipaddr can lead to out-of-bounds write. The attack may be performed from remote. The exploit has been published and may be used. Upgrading the affected component is recommended. The vendor was contacted early, responded in a very professional manner and quickly released a fixed version of the affected product.

Weakness: CWE-787, CWE-119

Which versions are affected by CVE-2026-3703?

It affects 1 product.

Products include Wavlink Wl-Nu516u1 Firmware.

How do I fix CVE-2026-3703?

No fix has been published for CVE-2026-3703 yet. Limit exposure of the affected software until one is available.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2026-3703 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-3703 exists.

Sources

Also known as GHSA-6rfc-r3c7-7f5j.