# CVE-2026-16517: Libarchive: libarchive: signed integer overflow in archive_write_zip_header

CVE-2026-16517 is fixed in 6 products on 1 platform, first by RHSA-2026:69553, released July 8, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-16517
- Priority: Routine
- CVSS: 3.9 (Low)
- EPSS: 0.0011
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 3, 2026
- Weakness: Integer Overflow or Wraparound
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-16517

## Description

A signed integer overflow vulnerability was found in libarchive's ZIP writer. In the archive_write_zip_header function in archive_write_set_format_zip.c, when ZIP encryption is enabled and the entry file size is close to INT64_MAX, the addition of the encryption overhead to the entry size overflows int64_t, resulting in undefined behavior. This could lead to incorrect Zip64 extension decisions or potential memory corruption.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | bsdtar almalinux 10 | 3.7.7-11.el10_2 | [ALSA-2026:69553](https://patchblox.com/security/data/fix/linux/alsa-2026-69553.md) | Sep 21, 2026 |
| Linux | bsdtar ol 10 | 0:3.7.7-11.el10_2 | [ELSA-2026-69553](https://patchblox.com/security/data/fix/linux/elsa-2026-69553.md) | Sep 23, 2026 |
| Linux | libarchive Debian 12.15 (bookworm) | 3.6.2-1+deb12u5 | [DEBIAN-CVE-2026-16517](https://patchblox.com/security/data/fix/linux/debian-cve-2026-16517.md) | Aug 7, 2026 |
| Linux | libarchive Debian 14 | 3.8.9-1 | [DEBIAN-CVE-2026-16517](https://patchblox.com/security/data/fix/linux/debian-cve-2026-16517.md) | Aug 7, 2026 |
| Linux | libarchive RHEL 10 | 3.7.7-11.el10_2 | [RHSA-2026:69553](https://patchblox.com/security/data/fix/linux/rhsa-2026-69553.md) | Jul 8, 2026 |
| Linux | libarchive almalinux 10 | 3.7.7-11.el10_2 | [ALSA-2026:69553](https://patchblox.com/security/data/fix/linux/alsa-2026-69553.md) | Sep 21, 2026 |
| Linux | libarchive ol 10 | 0:3.7.7-11.el10_2 | [ELSA-2026-69553](https://patchblox.com/security/data/fix/linux/elsa-2026-69553.md) | Sep 23, 2026 |
| Linux | libarchive rocky 10 | 0:3.7.7-11.el10_2 | [RLSA-2026:69553](https://patchblox.com/security/data/fix/linux/rlsa-2026-69553.md) | Sep 23, 2026 |
| Linux | libarchive-devel almalinux 10 | 3.7.7-11.el10_2 | [ALSA-2026:69553](https://patchblox.com/security/data/fix/linux/alsa-2026-69553.md) | Sep 21, 2026 |
| Linux | libarchive-devel ol 10 | 0:3.7.7-11.el10_2 | [ELSA-2026-69553](https://patchblox.com/security/data/fix/linux/elsa-2026-69553.md) | Sep 23, 2026 |
| Linux | libarchive-tools Ubuntu 22.04.1 LTS (jammy) | 3.6.0-1ubuntu1.9 | [libarchive-tools 3.6.0-1ubuntu1.9](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libarchive-tools-3.6.0-1ubuntu1.9.md) | Jul 21, 2026 |
| Linux | libarchive-tools Ubuntu 24.04.5 LTS (noble) | 3.7.2-2ubuntu0.9 | [libarchive-tools 3.7.2-2ubuntu0.9](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libarchive-tools-3.7.2-2ubuntu0.9.md) | Jul 21, 2026 |
| Linux | libarchive-tools Ubuntu 26.04.1 LTS (resolute) | 3.8.5-1ubuntu2.3 | [libarchive-tools 3.8.5-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libarchive-tools-3.8.5-1ubuntu2.3.md) | Jul 21, 2026 |
| Linux | libarchive13 Ubuntu 22.04.1 LTS (jammy) | 3.6.0-1ubuntu1.9 | [libarchive13 3.6.0-1ubuntu1.9](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libarchive13-3.6.0-1ubuntu1.9.md) | Jul 21, 2026 |
| Linux | libarchive13t64 Ubuntu 24.04.5 LTS (noble) | 3.7.2-2ubuntu0.9 | [libarchive13t64 3.7.2-2ubuntu0.9](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libarchive13t64-3.7.2-2ubuntu0.9.md) | Jul 21, 2026 |
| Linux | libarchive13t64 Ubuntu 26.04.1 LTS (resolute) | 3.8.5-1ubuntu2.3 | [libarchive13t64 3.8.5-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libarchive13t64-3.8.5-1ubuntu2.3.md) | Jul 21, 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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