CVE-2026-18588 Wavlink WL-NU516U1 nas.cgi fgets stack-based overflow

Critical 9.3 Published Updated

Remote attackers can execute arbitrary code via a stack-based buffer overflow in the nas.cgi component of Wavlink WL-NU516U1 devices.

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-2026-18588?

CVE-2026-18588 is a critical memory corruption vulnerability in Wavlink WL-NU516U1, published on 3 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A vulnerability has been found in Wavlink WL-NU516U1 708c073-mt7628. This affects the function fgets of the file nas.cgi. The manipulation of the argument CONTENT_LENGTH leads to stack-based buffer overflow. Remote exploitation of the attack is possible. You should 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.

Weakness: CWE-121, CWE-119

Which versions are affected by CVE-2026-18588?

How do I fix CVE-2026-18588?

No fix has been published for CVE-2026-18588 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-2026-18588 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-18588 exists.

Sources

Also known as GHSA-hfj9-7vrj-jwv3.

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