CVE-2026-56391

coreutils: GNU coreutils uniq is vulnerable to an out‑of‑bounds read due to incorrect handling of multibyte input when the -w (-...

CVE-2026-56391 is fixed in 9 products on 1 platform, first by gnu-coreutils 9.7-3ubuntu2.1, released July 24, 2026. It is not reported as exploited. Patch Radar priority: Routine.

Routine
CVSS
6.1
moderate
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0013
2nd percentile

GNU coreutils uniq is vulnerable to an out‑of‑bounds read due to incorrect handling of multibyte input when the -w (--check-chars) option is used. The find_field() function miscalculates the byte length of characters by repeatedly processing a fixed pointer instead of advancing through the input, resulting in an inflated length value. This incorrect length is later used in a memcmp operation, causing reads beyond the allocated buffer when processing crafted multibyte input. When running GNU coreutils uniq with attacker-provided arguments, this behavior leads to a crash and potential adjacent heap memory exposure. This issue has been fixed in the commit d64e35a8a4c0e4608321433e0d84d917e4e36371.

Where it's fixed

ProductFixed inFixReleased
Linux
coreutils · Fedora 43 9.7-10.fc43 FEDORA-2026-25427610BB Aug 3, 2026
coreutils · RHEL 10 9.5-8.el10_2.1 RHSA-2026:67886 Jul 24, 2026
coreutils · almalinux 10 9.5-8.el10_2.1 ALSA-2026:67886 Sep 16, 2026
coreutils · ol 10 0:9.5-8.0.1.el10_2.1 ELSA-2026-67886 Sep 16, 2026
coreutils · opensuse-leap 16.0 9.6-160000.3.1 OPENSUSE-SU-2026:22147-1 Nov 7, 2026
coreutils · rocky 10 0:9.5-8.el10_2.1 RLSA-2026:67886 Sep 17, 2026
coreutils · sles 16.0 9.6-160000.3.1 SUSE-SU-2026:24268-1 Nov 7, 2026
coreutils-common · Fedora 43 9.7-10.fc43 FEDORA-2026-25427610BB Aug 3, 2026
coreutils-common · almalinux 10 9.5-8.el10_2.1 ALSA-2026:67886 Sep 16, 2026
coreutils-common · ol 10 0:9.5-8.0.1.el10_2.1 ELSA-2026-67886 Sep 16, 2026
coreutils-debuginfo · Fedora 43 9.7-10.fc43 FEDORA-2026-25427610BB Aug 3, 2026
coreutils-debugsource · Fedora 43 9.7-10.fc43 FEDORA-2026-25427610BB Aug 3, 2026
coreutils-single · Fedora 43 9.7-10.fc43 FEDORA-2026-25427610BB Aug 3, 2026
coreutils-single · almalinux 10 9.5-8.el10_2.1 ALSA-2026:67886 Sep 16, 2026
coreutils-single · ol 10 0:9.5-8.0.1.el10_2.1 ELSA-2026-67886 Sep 16, 2026
coreutils-single · opensuse-leap 16.0 9.6-160000.3.1 OPENSUSE-SU-2026:22147-1 Nov 7, 2026
coreutils-single · sles 16.0 9.6-160000.3.1 SUSE-SU-2026:24268-1 Nov 7, 2026
coreutils-single-debuginfo · Fedora 43 9.7-10.fc43 FEDORA-2026-25427610BB Aug 3, 2026
coreutils-systemd · opensuse-leap 16.0 9.6-160000.3.1 OPENSUSE-SU-2026:22147-1 Nov 7, 2026
coreutils-systemd · sles 16.0 9.6-160000.3.1 SUSE-SU-2026:24268-1 Nov 7, 2026
coreutils-testsuite · opensuse-leap 16.0 9.6-160000.3.1 OPENSUSE-SU-2026:22147-1 Nov 7, 2026
gnu-coreutils · Ubuntu 26.04.1 LTS (resolute) 9.7-3ubuntu2.1 gnu-coreutils 9.7-3ubuntu2.1 Jul 24, 2026

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