CVE-2026-43359

Summary

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix transaction abort on set received ioctl due to item overflow If the set received ioctl fails due to an item overflow wh

Details

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix transaction abort on set received ioctl due to item overflow If the set received ioctl fails due to an item overflow when attempting to add the BTRFS_UUID_KEY_RECEIVED_SUBVOL we have to abort the transaction since we did some metadata updates before. This means that if a user calls this ioctl with the same received UUID field for a lot of subvolumes, we will hit the overflow, trigger the transaction abort and turn the filesystem into RO mode. A malicious user could exploit this, and this ioctl does not even requires that a user has admin privileges (CAP_SYS_ADMIN), only that he/she owns the subvolume. Fix this by doing an early check for item overflow before starting a transaction. This is also race safe because we are holding the subvol_sem semaphore in exclusive (write) mode. A test case for fstests will follow soon.

References

• https://git.kernel.org/stable/c/2e57b8cac2ba0d38aac76c1ecdfd8b899e3581a5
• https://git.kernel.org/stable/c/41fb97353ff58fa4f31904c343fc8e3df2f7517d
• https://git.kernel.org/stable/c/87f2c46003fce4d739138aab4af1942b1afdadac
• https://git.kernel.org/stable/c/b19c0465e4daad5aa8f60552ea0578cf31a11b1e
• https://git.kernel.org/stable/c/b9914db13ac15aca3b74544c0bb1a2e0dad1f174
• https://git.kernel.org/stable/c/d11aefe654a04fc41996d254748d6a38b6b0a7be