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
Coreutils: heap buffer under-read in gnu coreutils sort via key specification
A flaw was found in GNU Coreutils. The sort utility's begfield() function is vulnerable to a heap buffer under-read. The program may access memory outside the allocated buffer if a user runs a crafted command using the traditional key format. A malicious input could lead to a crash or leak sensitive data.