CVE-2026-56392: Heap-based Buffer Overflow in GNU coreutils
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 Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-56392?
CVE-2026-56392 has a risk score of 52, indicating a moderate level of severity.
How do I fix CVE-2026-56392?
To fix CVE-2026-56392, update to the latest version of GNU coreutils that addresses the heap-based buffer overflow.
What vulnerabilities are associated with CVE-2026-56392?
CVE-2026-56392 is associated with buffer overflow and integer overflow vulnerabilities.
What software is impacted by CVE-2026-56392?
GNU coreutils, specifically the unexpand command, is impacted by CVE-2026-56392.
What type of vulnerability is CVE-2026-56392?
CVE-2026-56392 is a heap-based buffer overflow vulnerability caused by an integer overflow during buffer allocation.