CVE-2026-56391

Summary

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.

Affected Software

VendorProductVersion RangeStatus
GNUcoreutils9.5 <= 9.11affected

Weaknesses

  • CWE-125: CWE-125 Out-of-bounds Read

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References