Linux Kernel btrfs CVE-2026-43308

Upgrade to Linux kernel version 6.19.6 or 7.0 or later, which include upstream fixes in commits c7d1d4ff56744074e005771aff193b927392d51f and 5549743e11c06da23cfa7712a994b9f1e69064c6. Distribution-specific patched kernels should be applied according to vendor security advisories. For systems where immediate patching is not feasible, consider switching critical filesystems from btrfs to ext4 or xfs if operationally viable, though this requires full data migration with associated downtime and risk. Restricting local user access and implementing mandatory access controls (SELinux, AppArmor) provides defense in depth but does not prevent exploitation by legitimately authenticated users. Monitor kernel logs for btrfs-related errors as potential indicators of exploitation attempts or filesystem corruption issues. The patch itself is low-risk (converts kernel panic to error return) so update confidence is high with minimal regression risk. No known workarounds exist that prevent the vulnerable code path from being reached while maintaining normal btrfs functionality.