PT-2026-64260 · Gnu · Coreutils

Marcin Wyczechowski + 1 · CVE-2026-56392 · Published 2026-07-24 · Updated 2026-07-24

NVD

CVSS v4.0

1.8

Low

Base vector

AV:L/AC:L/AT:P/PR:N/UI:A/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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

Fix

Heap Based Buffer Overflow

Weakness Enumeration

CWE-122

Related Identifiers

CVE-2026-56392

Affected Products

Coreutils

References · 4

• https://git.savannah.gnu.org/cgit/coreutils.git/commit/?id=b60a159fdc5bfcf9988d3a4cb6f53abe8ad5d35d · Patch
• https://nvd.nist.gov/vuln/detail/CVE-2026-56392 · Security Note
• https://git.savannah.gnu.org/cgit/coreutils.git · Note
• https://cert.pl/en/posts/2026/07/CVE-2026-56391 · Note