CVE-2026-56392

CVE Details

Release Date:	2026-07-24
Impact:	Moderate	What is this?

Description

GNU coreutils unexpand is vulnerable to a heap-based buffer overflow due to an integer overflow during buffer allocation when processing large tab stop (-t) values. The multiplication used to calculate the allocation size can wrap around, resulting in an undersized buffer. When processing crafted input, subsequent writes exceed the allocated memory, leading to an out-of-bounds heap write. When running GNU coreutils unexpand with attacker-provided large tab stop (-t) arguments, this behavior leads to a crash and potentially achieve a heap write primitive depending on memory layout. This issue has been fixed in the commit b60a159fdc5bfcf9988d3a4cb6f53abe8ad5d35d

See more information about CVE-2026-56392 from MITRE CVE dictionary and NIST NVD

NOTE: The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 metrics

Base Score:	4.4
Vector String:	CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L
Version:	3.1
Attack Vector:	Local
Attack Complexity:	Low
Privileges Required:	None
User Interaction:	Required
Scope:	Unchanged
Confidentiality Impact:	None
Integrity Impact:	Low
Availability Impact:	Low

Errata information

Platform	Errata	Release Date
Oracle Linux version 9 (coreutils)	ELSA-2026-66403-0	2026-09-10