Copyright © 2012 Red Hat, Inc. All rights reserved. Moderate 2026-07-24T07:44:45 coreutils: GNU coreutils uniq: Denial of Service and information disclosure via out-of-bounds read with multibyte input 6.1 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H CWE-125

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.

A flaw was found in GNU coreutils uniq. When processing specially crafted multibyte input with the --check-chars option, an attacker can trigger an out-of-bounds read. This vulnerability can lead to a denial of service (DoS) due to an application crash and potentially expose sensitive information from adjacent memory.

This Moderate flaw in GNU coreutils `uniq` allows an out-of-bounds read when processing specially crafted multibyte input with the `--check-chars` option. An attacker providing malicious input to `uniq` could trigger a denial of service due to an application crash, and potentially disclose adjacent heap memory. Exploitation requires local user interaction to execute `uniq` with the vulnerable options and input. Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability. Red Hat Hardened Images 2026-07-27T00:00:00Z RHSA-2026:46515 coreutils-main-9.11-5.1.hum1 Red Hat Enterprise Linux 10 Affected coreutils Red Hat Enterprise Linux 6 Out of support scope coreutils Red Hat Enterprise Linux 7 Out of support scope coreutils Red Hat Enterprise Linux 8 Fix deferred coreutils Red Hat Enterprise Linux 9 Fix deferred coreutils Red Hat OpenShift Container Platform 4 Under investigation rhcos https://www.cve.org/CVERecord?id=CVE-2026-56391 https://nvd.nist.gov/vuln/detail/CVE-2026-56391 https://cert.pl/en/posts/2026/07/CVE-2026-56391 https://git.savannah.gnu.org/cgit/coreutils.git/ https://git.savannah.gnu.org/cgit/coreutils.git/commit/?id=d64e35a8a4c0e4608321433e0d84d917e4e36371