# CVE-2026-66486: Improper Output Encoding in GNU cpio

CVE-2026-66486 is fixed in 2 products on 1 platform, first by cpio 2.15+dfsg-2.1ubuntu0.1, released August 10, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-66486
- Priority: Routine
- CVSS: n/a (Moderate)
- EPSS: 0.0018
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 10, 2026
- Weakness: Improper Encoding or Escaping of Output
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66486

## Description

GNU cpio is vulnerable to improper encoding or escaping of output in its archive member listing functionality. When listing archive members via cpio -it, member names are printed directly to output without quoting or escaping. An attacker can craft a cpio archive containing member names with embedded newline characters or ANSI escape sequences, causing forged listing entries or terminal control sequence injection when the listing is displayed. This issue has been fixed in commit 2ff9600c9ef32e88759843cdbde74c8db5ae9b30

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | cpio Ubuntu 18.04.6 LTS (bionic) | 2.12+dfsg-6ubuntu0.18.04.4+esm1 | [cpio 2.12+dfsg-6ubuntu0.18.04.4+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-cpio-2.12-dfsg-6ubuntu0.18.04.4-esm1.md) | Sep 3, 2026 |
| Linux | cpio Ubuntu 20.04 LTS (focal) | 2.13+dfsg-2ubuntu0.4+esm1 | [cpio 2.13+dfsg-2ubuntu0.4+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-cpio-2.13-dfsg-2ubuntu0.4-esm1.md) | Sep 3, 2026 |
| Linux | cpio Ubuntu 22.04.1 LTS (jammy) | 2.13+dfsg-7ubuntu0.2 | [cpio 2.13+dfsg-7ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-cpio-2.13-dfsg-7ubuntu0.2.md) | Sep 3, 2026 |
| Linux | cpio Ubuntu 24.04.5 LTS (noble) | 2.15+dfsg-1ubuntu2.1 | [cpio 2.15+dfsg-1ubuntu2.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-cpio-2.15-dfsg-1ubuntu2.1.md) | Sep 3, 2026 |
| Linux | cpio Ubuntu 26.04.1 LTS (resolute) | 2.15+dfsg-2.1ubuntu0.1 | [cpio 2.15+dfsg-2.1ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-cpio-2.15-dfsg-2.1ubuntu0.1.md) | Aug 10, 2026 |
| Linux | cpio opensuse-leap 16.0 | 2.15-160000.3.1 | [OPENSUSE-SU-2026:21747-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21747-1.md) | Sep 3, 2026 |
| Linux | cpio sles 15.7 | 2.13-150400.3.10.1 | [SUSE-SU-2026:4012-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4012-1.md) | Sep 7, 2026 |
| Linux | cpio sles 16.0 | 2.15-160000.3.1 | [SUSE-SU-2026:23612-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23612-1.md) | Sep 3, 2026 |
| Linux | cpio-win32 Ubuntu 18.04.6 LTS (bionic) | 2.12+dfsg-6ubuntu0.18.04.4+esm1 | [cpio-win32 2.12+dfsg-6ubuntu0.18.04.4+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-cpio-win32-2.12-dfsg-6ubuntu0.18.04.4-esm1.md) | Sep 3, 2026 |
| Linux | cpio-win32 Ubuntu 20.04 LTS (focal) | 2.13+dfsg-2ubuntu0.4+esm1 | [cpio-win32 2.13+dfsg-2ubuntu0.4+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-cpio-win32-2.13-dfsg-2ubuntu0.4-esm1.md) | Sep 3, 2026 |
| Linux | cpio-win32 Ubuntu 22.04.1 LTS (jammy) | 2.13+dfsg-7ubuntu0.2 | [cpio-win32 2.13+dfsg-7ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-cpio-win32-2.13-dfsg-7ubuntu0.2.md) | Sep 3, 2026 |

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Data as of 2026-11-09T13:31:49Z 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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