CVE-2026-40553 Stack-based buffer overflow in gawk

Medium 5.1 Published 13 Jul 2026 Updated 13 Jul 2026

A stack-based buffer overflow in gawk allows attackers to crash the program and potentially execute arbitrary code.

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-2026-40553?

CVE-2026-40553 is a medium-severity memory corruption 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

Buffer overflow vulnerability has been found in "extension/readdir.c" program file of gawk (ftype() routine). This issue could be used to crash the program and potentially to achieve code execution, although the latter has not been confirmed to be feasible. It affects gawk in versions 5.4.0 and below.

Weakness: CWE-121

Which versions are affected by CVE-2026-40553?

It affects 1 product.

Products include Fossies Gawk.

How do I fix CVE-2026-40553?

Apply the vendor's patch.

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

Is CVE-2026-40553 being exploited?

There is no known exploitation of CVE-2026-40553 in the wild and no public exploit code.

Sources

Also known as AZL-92283, BELL-CVE-2026-40553, DEBIAN-CVE-2026-40553, ECHO-6a06-58a4-e150, GHSA-3j4c-7g5m-7rg5, JLSEC-2026-788 and 1 more.