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 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.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxdd5f9615fc5c5e8d3751aab3a17b92768fb1ce70 < b9914db13ac15aca3b74544c0bb1a2e0dad1f174affected
LinuxLinuxdd5f9615fc5c5e8d3751aab3a17b92768fb1ce70 < b19c0465e4daad5aa8f60552ea0578cf31a11b1eaffected
LinuxLinuxdd5f9615fc5c5e8d3751aab3a17b92768fb1ce70 < 2e57b8cac2ba0d38aac76c1ecdfd8b899e3581a5affected
LinuxLinuxdd5f9615fc5c5e8d3751aab3a17b92768fb1ce70 < d11aefe654a04fc41996d254748d6a38b6b0a7beaffected
LinuxLinuxdd5f9615fc5c5e8d3751aab3a17b92768fb1ce70 < 41fb97353ff58fa4f31904c343fc8e3df2f7517daffected
LinuxLinuxdd5f9615fc5c5e8d3751aab3a17b92768fb1ce70 < 87f2c46003fce4d739138aab4af1942b1afdadacaffected
LinuxLinux3.12affected
LinuxLinux0 < 3.12unaffected
LinuxLinux6.1.167 <= 6.1.*unaffected
LinuxLinux6.6.130 <= 6.6.*unaffected
LinuxLinux6.12.78 <= 6.12.*unaffected
LinuxLinux6.18.19 <= 6.18.*unaffected
LinuxLinux6.19.9 <= 6.19.*unaffected
LinuxLinux7.0 <= *unaffected

Weaknesses

References