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.

Routine

CVSS

n/a

Moderate

Exploitation

None reported

No vendor assessment

CISA KEV

Not listed

Not in the Known Exploited Vulnerabilities catalog

EPSS

0.0018

8th percentile

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

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	Sep 3, 2026
cpio · Ubuntu 20.04 LTS (focal)	2.13+dfsg-2ubuntu0.4+esm1	cpio 2.13+dfsg-2ubuntu0.4+esm1	Sep 3, 2026
cpio · Ubuntu 22.04.1 LTS (jammy)	2.13+dfsg-7ubuntu0.2	cpio 2.13+dfsg-7ubuntu0.2	Sep 3, 2026
cpio · Ubuntu 24.04.5 LTS (noble)	2.15+dfsg-1ubuntu2.1	cpio 2.15+dfsg-1ubuntu2.1	Sep 3, 2026
cpio · Ubuntu 26.04.1 LTS (resolute)	2.15+dfsg-2.1ubuntu0.1	cpio 2.15+dfsg-2.1ubuntu0.1	Aug 10, 2026
cpio · opensuse-leap 16.0	2.15-160000.3.1	OPENSUSE-SU-2026:21747-1	Sep 3, 2026
cpio · sles 15.7	2.13-150400.3.10.1	SUSE-SU-2026:4012-1	Sep 7, 2026
cpio · sles 16.0	2.15-160000.3.1	SUSE-SU-2026:23612-1	Sep 3, 2026
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	Sep 3, 2026
cpio-win32 · Ubuntu 20.04 LTS (focal)	2.13+dfsg-2ubuntu0.4+esm1	cpio-win32 2.13+dfsg-2ubuntu0.4+esm1	Sep 3, 2026
cpio-win32 · Ubuntu 22.04.1 LTS (jammy)	2.13+dfsg-7ubuntu0.2	cpio-win32 2.13+dfsg-7ubuntu0.2	Sep 3, 2026

Details

Published
August 10, 2026
Weakness
Improper Encoding or Escaping of Output
Vendor advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66486

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