CVE-2026-40469: Integer overflow vulnerability has been found in "builtin.c" program file of gawk (do_sub() routine)

Q: How do I fix CVE-2026-40469?

gawk: upgrade to newer than 5.4.0. Exact commands for each OS are on this page.

Q: Is CVE-2026-40469 being exploited?

CVE-2026-40469 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-40469 affect?

CVE-2026-40469 affects gawk. Severity is critical (CVSS 9.1). 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 ver

Q: How urgent is CVE-2026-40469?

Priority 40/100. Critical severity; Remotely exploitable, no login, no user action

This month

CRITICAL 9.1REMOTEUPGRADE

CVE-2026-40469 is a critical-severity flaw (CVSS 9.1) affecting gawk. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 89%)
CISA exploited list	No
Weakness	CWE-190
Published	2026-07-13
Last modified	2026-10-24

Publisher (CNA): CERT.PL · Vendor: fossies

Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-13 13:16 UTCPublished CVE record published
2026-10-24 22:10 UTCUpdated Record last modified

fossies gawk UPGRADE

Affected: <= 5.4.0

Fixed in: newer than 5.4.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy gawk || rpm -q gawk || gawk --version

2. UPGRADE to newer than 5.4.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade gawk

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade gawk

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Advisories and coverage

Official advisories

CERT Polska: Vulnerabilities in GNU gawk software 2026-07-13

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-40469?

gawk: upgrade to newer than 5.4.0. Exact commands for each OS are on this page.

Is CVE-2026-40469 being exploited?

CVE-2026-40469 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-40469 affect?

CVE-2026-40469 affects gawk. Severity is critical (CVSS 9.1). 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 ver

How urgent is CVE-2026-40469?

Priority 40/100. Critical severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-40468 CRITICAL 9.1 UPGRADE Integer overflow vulnerability has been found in "builtin.c" program file of gawk
CVE-2026-40553 HIGH 7.5 UPGRADE Buffer overflow vulnerability has been found in "extension/readdir.c" program file of gawk (ftype() routine)
CVE-2026-40467 HIGH 7.5 UPGRADE Use After Free vulnerability has been found in "io.c" program file of gawk (do_getline_redir() routine)

References

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