Vulnerability Description
GNU coreutils uniq is vulnerable to an out‑of‑bounds read due to incorrect handling of multibyte input when the -w (--check-chars) option is used. The find_field() function miscalculates the byte length of characters by repeatedly processing a fixed pointer instead of advancing through the input, resulting in an inflated length value. This incorrect length is later used in a memcmp operation, causing reads beyond the allocated buffer when processing crafted multibyte input. When running GNU coreutils uniq with attacker-provided arguments, this behavior leads to a crash and potential adjacent heap memory exposure. This issue has been fixed in the commit d64e35a8a4c0e4608321433e0d84d917e4e36371.
Related Weaknesses (CWE)
References
- https://cert.pl/en/posts/2026/07/CVE-2026-56391
- https://git.savannah.gnu.org/cgit/coreutils.git/
- https://git.savannah.gnu.org/cgit/coreutils.git/commit/?id=d64e35a8a4c0e46083214
FAQ
What is CVE-2026-56391?
CVE-2026-56391 is a documented vulnerability. GNU coreutils uniq is vulnerable to an out‑of‑bounds read due to incorrect handling of multibyte input when the -w (--check-chars) option is used. The find_field() function miscalculates the byte leng...
How severe is CVE-2026-56391?
CVSS scoring is not yet available for CVE-2026-56391. Check NVD for updates.
Is there a patch for CVE-2026-56391?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.