CVE-2026-35353: uutils coreutils has a Time-of-check Time-of-use (TOCTOU) Race Condition

The mkdir utility in uutils coreutils incorrectly applies permissions when using the -m flag by creating a directory with umask-derived permissions (typically 0755) before subsequently changing them to the requested mode via a separate chmod system call. In multi-user environments, this introduces a brief window where a directory intended to be private is accessible to other users, potentially leading to unauthorized data access.