Null Pointer Dereference in Btrfs Affects Linux Kernel Products

CVE-2026-64593

What is CVE-2026-64593?

A vulnerability in the Btrfs filesystem within the Linux kernel has been identified that results in a null pointer dereference due to improper handling of device states. Specifically, when a device is marked as missing and later re-scanned, the BTRFS_DEV_STATE_WRITEABLE flag may not be set, leaving the device's bdev pointer as NULL. This can cause the filesystem to crash during operations that attempt to trim free extents, leading to potential service disruptions. Proper synchronization and management of device state transitions are essential for maintaining system stability and preventing such errors.

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