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

CVE-2026-40553 is fixed in 6 products on 1 platform, first by gawk 1:5.3.2-1ubuntu1.1, released July 13, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-40553
- Priority: Routine
- CVSS: 6.2 (Moderate)
- EPSS: 0.0029
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 13, 2026
- Weakness: Stack-based Buffer Overflow
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40553

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | gawk RHEL 10 | 5.3.0-6.el10_2.1 | [RHSA-2026:73429](https://patchblox.com/security/data/fix/linux/rhsa-2026-73429.md) | Jul 13, 2026 |
| Linux | gawk RHEL 9 | 0:5.1.0-6.el9_8.1 | [RHSA-2026:73512](https://patchblox.com/security/data/fix/linux/rhsa-2026-73512.md) | Sep 30, 2026 |
| Linux | gawk Ubuntu 26.04.1 LTS (resolute) | 1:5.3.2-1ubuntu1.1 | [gawk 1:5.3.2-1ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-gawk-1-5.3.2-1ubuntu1.1.md) | Jul 13, 2026 |
| Linux | gawk almalinux 10 | 5.3.0-6.el10_2.1 | [ALSA-2026:73429](https://patchblox.com/security/data/fix/linux/alsa-2026-73429.md) | Sep 29, 2026 |
| Linux | gawk almalinux 9 | 5.1.0-6.el9_8.1 | [ALSA-2026:73512](https://patchblox.com/security/data/fix/linux/alsa-2026-73512.md) | Sep 29, 2026 |
| Linux | gawk amzn 2023 | 5.1.0-3.amzn2023.0.4 | [ALAS2023-2026-2035](https://patchblox.com/security/data/fix/linux/alas2023-2026-2035.md) | Aug 3, 2026 |
| Linux | gawk ol 10 | 0:5.3.0-6.el10_2.1 | [ELSA-2026-73429](https://patchblox.com/security/data/fix/linux/elsa-2026-73429.md) | Sep 30, 2026 |
| Linux | gawk ol 9 | 0:5.1.0-6.el9_8.1 | [ELSA-2026-73512](https://patchblox.com/security/data/fix/linux/elsa-2026-73512.md) | Sep 30, 2026 |
| Linux | gawk opensuse-leap 16.0 | 5.3.2-160000.3.1 | [OPENSUSE-SU-2026:21393-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21393-1.md) | Jul 20, 2026 |
| Linux | gawk rocky 10 | 0:5.3.0-6.el10_2.1 | [RLSA-2026:73429](https://patchblox.com/security/data/fix/linux/rlsa-2026-73429.md) | Sep 30, 2026 |
| Linux | gawk rocky 9 | 0:5.1.0-6.el9_8.1 | [RLSA-2026:73512](https://patchblox.com/security/data/fix/linux/rlsa-2026-73512.md) | Sep 30, 2026 |
| Linux | gawk sles 15.7 | 4.2.1-150000.3.6.1 | [SUSE-SU-2026:3455-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3455-1.md) | Aug 3, 2026 |
| Linux | gawk sles 16.0 | 5.3.2-160000.3.1 | [SUSE-SU-2026:22831-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-22831-1.md) | Jul 20, 2026 |
| Linux | gawk-all-langpacks RHEL 9 | 0:5.1.0-6.el9_8.1 | [RHSA-2026:73512](https://patchblox.com/security/data/fix/linux/rhsa-2026-73512.md) | Sep 30, 2026 |
| Linux | gawk-all-langpacks almalinux 10 | 5.3.0-6.el10_2.1 | [ALSA-2026:73429](https://patchblox.com/security/data/fix/linux/alsa-2026-73429.md) | Sep 29, 2026 |
| Linux | gawk-all-langpacks almalinux 9 | 5.1.0-6.el9_8.1 | [ALSA-2026:73512](https://patchblox.com/security/data/fix/linux/alsa-2026-73512.md) | Sep 29, 2026 |
| Linux | gawk-all-langpacks amzn 2023 | 5.1.0-3.amzn2023.0.4 | [ALAS2023-2026-2035](https://patchblox.com/security/data/fix/linux/alas2023-2026-2035.md) | Aug 3, 2026 |
| Linux | gawk-all-langpacks ol 10 | 0:5.3.0-6.el10_2.1 | [ELSA-2026-73429](https://patchblox.com/security/data/fix/linux/elsa-2026-73429.md) | Sep 30, 2026 |
| Linux | gawk-all-langpacks ol 9 | 0:5.1.0-6.el9_8.1 | [ELSA-2026-73512](https://patchblox.com/security/data/fix/linux/elsa-2026-73512.md) | Sep 30, 2026 |
| Linux | gawk-debuginfo amzn 2023 | 5.1.0-3.amzn2023.0.4 | [ALAS2023-2026-2035](https://patchblox.com/security/data/fix/linux/alas2023-2026-2035.md) | Aug 3, 2026 |
| Linux | gawk-debugsource amzn 2023 | 5.1.0-3.amzn2023.0.4 | [ALAS2023-2026-2035](https://patchblox.com/security/data/fix/linux/alas2023-2026-2035.md) | Aug 3, 2026 |
| Linux | gawk-devel amzn 2023 | 5.1.0-3.amzn2023.0.4 | [ALAS2023-2026-2035](https://patchblox.com/security/data/fix/linux/alas2023-2026-2035.md) | Aug 3, 2026 |
| Linux | gawk-doc amzn 2023 | 5.1.0-3.amzn2023.0.4 | [ALAS2023-2026-2035](https://patchblox.com/security/data/fix/linux/alas2023-2026-2035.md) | Aug 3, 2026 |

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Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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