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

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-13 · updated 2026-10-24
Weakness: CWE-121

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.

Affected products

GNU gawk: through 5.4.0

References

https://cert.pl/en/posts/2026/07/CVE-2026-40467
https://cgit.git.savannah.gnu.org/cgit/gawk.git/commit/?id=cca0366144336b49aaa7d5d949966ce8e2c70843

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