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
Published: 2026-07-24
Score: 1.8 Low
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
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Remediation

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History

Fri, 24 Jul 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 24 Jul 2026 09:45:00 +0000

Type Values Removed Values Added
First Time appeared Gnu
Gnu coreutils
Vendors & Products Gnu
Gnu coreutils

Fri, 24 Jul 2026 08:15:00 +0000

Type Values Removed Values Added
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
Title Heap-based Buffer Overflow in GNU coreutils
Weaknesses CWE-122
References
Metrics cvssV4_0

{'score': 1.8, 'vector': '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'}


cve-icon MITRE

Status: PUBLISHED

Assigner: CERT-PL

Published:

Updated: 2026-07-24T12:32:14.074Z

Reserved: 2026-06-21T11:40:32.790Z

Link: CVE-2026-56392

cve-icon Vulnrichment

Updated: 2026-07-24T12:32:08.623Z

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-07-24T09:30:08Z

Weaknesses