CVE-2026-56392 | GNU coreutils unexpand is vulnerable to a heap-based buffer … | CVSS 1.8 LOW

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

Metadata

CVE ID: CVE-2026-56392
State: PUBLISHED
Assigner: CERT-PL
Reserved: 2026-06-21 11:40 UTC
Published: 2026-07-24 07:44 UTC
Last updated: 2026-07-24 07:44 UTC
Primary CWE: CWE-122
CWE-122 Heap-based Buffer Overflow
Vendor / Product: GNU / coreutils
Sources: cve.org · NVD

Severity & Metrics

1.8 LOW CVSS 4.0

CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N

Affected products (1)

Vendor	Product	Platform	Versions
GNU	coreutils	—	0 ≤ 9.11

Weakness (CWE)

CWE	Source	Description
CWE-122	cna	CWE-122 Heap-based Buffer Overflow

CVSS scores (1)

Score	Severity	Version	Source	Vector
1.8	LOW	4.0	cna	CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N

References (3)