CVE-2026-40553: Buffer overflow vulnerability has been found in "extension/readdir.c" program file of gawk (ftype() routine)

Q: How do I fix CVE-2026-40553?

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

Q: Is CVE-2026-40553 being exploited?

CVE-2026-40553 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-2026-40553 affect?

CVE-2026-40553 affects gawk. Severity is high (CVSS 7.5). 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 confirme

Q: How urgent is CVE-2026-40553?

Priority 36/100. High severity; Remotely exploitable, no login, no user action

Routine

HIGH 7.5REMOTEUPGRADE

CVE-2026-40553 is a high-severity flaw (CVSS 7.5) affecting gawk. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 79%)
CISA exploited list	No
Weakness	CWE-121
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-2026-40553?

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

Is CVE-2026-40553 being exploited?

CVE-2026-40553 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-2026-40553 affect?

CVE-2026-40553 affects gawk. Severity is high (CVSS 7.5). 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 confirme

How urgent is CVE-2026-40553?

Priority 36/100. High severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-40469 CRITICAL 9.1 UPGRADE Integer overflow vulnerability has been found in "builtin.c" program file of gawk (do_sub() routine)
CVE-2026-40468 CRITICAL 9.1 UPGRADE Integer overflow vulnerability has been found in "builtin.c" program file of gawk
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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