Linux Kernel CVE-2026-46159

The primary fix is to upgrade to a patched Linux kernel release: 6.6.140 or later for the 6.6.x LTS branch, 6.12.90 or later for the 6.12.x branch, 7.0.7 or later for the 7.0.x branch, 6.18.32 or later for the 6.18.x branch, or 7.1-rc1 or later for mainline - per EUVD-2026-32786 and the upstream commits at https://git.kernel.org/stable/c/f5ee467b56764964027c361641f64953fc0f8f9a and related links. Distributions (Debian, Ubuntu, RHEL, SUSE) should be monitored for backported kernel updates incorporating these commits. As a compensating control where patching is not immediately feasible, restricting the use of btrfs filesystems to trusted users only limits exploitation surface, since the attack requires a local user capable of issuing ioctl calls against a btrfs-mounted volume; note that this does not eliminate the vulnerability but removes unprivileged access. Disabling btrfs entirely (if the system uses ext4/xfs instead) eliminates the attack path entirely with no functional trade-off for non-btrfs workloads. No workaround exists that preserves full btrfs functionality while blocking the race without the kernel patch.