PT-2026-64259 · Gnu · Coreutils

Marcin Wyczechowski + 1 · CVE-2026-56391 · Published 2026-07-24 · Updated 2026-07-24

Mitre

CVSS v4.0

4.6

Medium

Base vector

AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N

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.

Fix

Out of bounds Read

Weakness Enumeration

CWE-125

Related Identifiers

CVE-2026-56391

Affected Products

Coreutils

References · 4

• https://git.savannah.gnu.org/cgit/coreutils.git/commit/?id=d64e35a8a4c0e4608321433e0d84d917e4e36371 · Patch
• https://nvd.nist.gov/vuln/detail/CVE-2026-56391 · Security Note
• https://git.savannah.gnu.org/cgit/coreutils.git · Note
• https://cert.pl/en/posts/2026/07/CVE-2026-56391 · Note