CVE-2026-93800

A flaw was found in the Linux kernel's Btrfs file system. A local user could cause a Denial of Service (DoS) or memory corruption due to improper error handling during subvolume relocation. If a failure occurs while updating relocation data, the kernel can leave an invalid reference pointing to memory that has already been released. When the file system is later unmounted, accessing this freed memory triggers a use-after-free flaw, leading to a kernel crash.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Disallow loading of the Btrfs kernel module if Btrfs file systems are not required.

1. Prevent the module from autoloading by creating a configuration file:

echo "install btrfs /bin/true" > /etc/modprobe.d/btrfs.conf

2. If the module is already loaded, attempt to remove it:

modprobe -r btrfs

Caveat: Applying this configuration prevents any Btrfs file systems from being mounted. If Btrfs is currently in use by active mounts, unloading the module will fail, and a system reboot will be required for the change to take full effect.