CVE-2026-40467 PUBLISHED

Use after free in gawk

Assigner: CERT-PL
Reserved: 13.04.2026 Published: 13.07.2026 Updated: 13.07.2026

Use After Free vulnerability has been found in "io.c" program file of gawk (do_getline_redir() routine). This issue may lead to a crash. It affects gawk in versions 5.4.0 and below.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
CVSS Score: 5.1

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Local	Confidentiality	None	Confidentiality	None
Attack Complexity	Low	Integrity	None	Integrity	None
Attack Requirements	None	Availability	Low	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

Product Status

Vendor	GNU
Product	gawk
Versions	Default: unaffected affected from 0 to 5.4.0 (incl.)

Credits

Michał Majchrowicz (AFINE) finder
Marcin Wyczechowski (AFINE) finder

References

https://cgit.git.savannah.gnu.org/cgit/gawk.git/commit/?id=a2d18c74109e41bec29a23098eba2e00057286d8
https://cert.pl/en/posts/2026/07/CVE-2026-40467

Problem Types

CWE-416 Use After Free CWE