CVE-2026-40469 Heap buffer overflow in gawk

Medium 5.1 Published 13 Jul 2026 Updated 13 Jul 2026

An integer overflow in gawk's do_sub routine allows attackers to crash the program via heap metadata corruption on 32-bit builds.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2026-40469?

CVE-2026-40469 is a medium-severity vulnerability in GNU gawk, published on 13 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

Integer overflow vulnerability has been found in "builtin.c" program file of gawk (do_sub() routine). This issue could be used to overwrite gawk heap metadata and objects causing the program to crash. It affects 32-bit builds of gawk in versions 5.4.0 and below.

Weakness: CWE-190

Which versions are affected by CVE-2026-40469?

It affects 1 product.

Products include Fossies Gawk.

How do I fix CVE-2026-40469?

Apply the vendor's patch.

Is CVE-2026-40469 being exploited?

There is no known exploitation of CVE-2026-40469 in the wild and no public exploit code.

Sources

Also known as BELL-CVE-2026-40469, CLSA-2026-1784303038, CLSA-2026-1787229301, CLSA-2026-1792441187, DEBIAN-CVE-2026-40469, ECHO-e2f2-918d-5b78 and 3 more.