High severity · published Jul 13, 2026
CVE-2026-40553
Stack-based buffer overflow in gawk
7.5
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 21% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
GA
gawk · GNU
through 5.4.0 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-40553
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-40553
Third Party Advisory
https://cert.pl/en/posts/2026/07/CVE-2026-40467
Patch
https://cgit.git.savannah.gnu.org/cgit/gawk.git/commit/?id=cca0366144336b49aaa7d5d949966ce8e2c70843
More from gawk
9.1
CVE-2026-40469
Heap buffer overflow in gawk
9.1
CVE-2026-40468
Heap buffer overflow in gawk
7.5
CVE-2026-40467
Use after free in gawk
7.1
CVE-2023-4156
A heap out-of-bounds read flaw was found in builtin.c in the gawk package