Bug 2507449 - CVE-2026-56391 coreutils: GNU coreutils uniq: Denial of Service and information disclosure via out-of-bounds read with multibyte input [fedora-all]
Summary: CVE-2026-56391 coreutils: GNU coreutils uniq: Denial of Service and informati...
Keywords:
Status: NEW
Alias: None
Product: Fedora
Classification: Fedora
Component: coreutils
Version: rawhide
Hardware: Unspecified
OS: Unspecified
medium
medium
Target Milestone: ---
Assignee: Lukáš Zaoral
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard: {"flaws": ["54809671-c38a-4098-9d24-6...
Depends On:
Blocks: CVE-2026-56391
TreeView+ depends on / blocked
 
Reported: 2026-07-27 12:05 UTC by Ganesh
Modified: 2026-07-27 12:05 UTC (History)
9 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Type: ---
Embargoed:


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Description Ganesh 2026-07-27 12:05:08 UTC
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

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.


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