Vulnerability · Published Jul 24, 2026 · Assigned by CERT-PL
CVE-2026-56392Heap-based Buffer Overflow in GNU coreutils
Low 1.8
In plain English
A low-severity heap buffer overflow in coreutils from GNU. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 8% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | coreutils | 9.5-8.el10_2.1 | ALSA-2026:67886 |
| AlmaLinux:9 | coreutils | 8.32-41.el9_8.1 | ALSA-2026:66403 |
| AlmaLinux:10 | coreutils-common | 9.5-8.el10_2.1 | ALSA-2026:67886 |
| AlmaLinux:9 | coreutils-common | 8.32-41.el9_8.1 | ALSA-2026:66403 |
| AlmaLinux:10 | coreutils-single | 9.5-8.el10_2.1 | ALSA-2026:67886 |
| AlmaLinux:9 | coreutils-single | 8.32-41.el9_8.1 | ALSA-2026:66403 |
| Debian:12 | coreutils | no fix listed | DEBIAN-CVE-2026-56392 |
| Debian:13 | coreutils | no fix listed | DEBIAN-CVE-2026-56392 |
| Debian:14 | coreutils | no fix listed | DEBIAN-CVE-2026-56392 |
| Rocky Linux:10 | coreutils | 0:9.5-8.el10_2.1 | RLSA-2026:67886 |
| Rocky Linux:9 | coreutils | 0:8.32-41.el9_8.1 | RLSA-2026:66403 |
| Ubuntu:22.04:LTS | coreutils | no fix listed | UBUNTU-CVE-2026-56392 |
| Ubuntu:24.04:LTS | coreutils | no fix listed | UBUNTU-CVE-2026-56392 |
| Ubuntu:26.04:LTS | coreutils | no fix listed | UBUNTU-CVE-2026-56392 |
Affected products (as reported)
Weakness: CWE-122 · 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