SB20260507248 - Always-Incorrect Control Flow Implementation in Linux kernel btrfs

Description

This security bulletin contains information about 1 vulnerability.

1) Always-Incorrect Control Flow Implementation (CVE-ID: CVE-2026-43118)

CWE-ID: CWE-670 - Always-Incorrect Control Flow Implementation

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a local user to cause data corruption.

The vulnerability exists due to improper handling of inode size during log replay in btrfs inode logging and log replay code when replaying a filesystem log after specific inode operations. A local user can create and truncate a file, create a hard link or rename it, and trigger log replay to cause data corruption.

The issue occurs when an inode with a new size of 0 is later logged in exists mode, causing the preserved size from the subvolume tree to remain non-zero after replay.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/03e966b63df5b06790310c1faaf3e0cb43adea8b
• https://git.kernel.org/stable/c/5254d4181add9dfaa5e3519edd71cc8f752b2f85
• https://git.kernel.org/stable/c/fddb157536e67a055597f00a8b4922d5f5ed0826