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

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.9% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-03-08 · updated 2026-06-17
Weakness: CWE-119

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.

Affected products

Wavlink NU516U1: 251208

References

https://dl.wavlink.com/firmware/RD/WINSTAR_NU516U1-WO-A-2026-02-27-2fcf6ae-mt7628-squashfs-sysupgrade.bin
https://github.com/Wlz1112/Wavlink-NU516U1-V251208-/blob/main/ipaddr.md
https://github.com/Wlz1112/Wavlink-NU516U1-V251208-/blob/main/ipaddr.md#exp-exploit--poc
https://vuldb.com/?ctiid.349649
https://vuldb.com/?id.349649
https://vuldb.com/?submit.759226

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