Race condition in Linux kernel - CVE-2026-53368

Vulnerability identifier: #VU138899

CSH Severity: Low

CVSS v4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-53368

CWE-ID: CWE-362

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to cause file system inconsistency.

The vulnerability exists due to a race condition in f2fs nat_entry flag handling in fs/f2fs/node.c when syncing files and writing checkpoints concurrently. A local user can trigger file write, fsync, and checkpoint activity to cause file system inconsistency.

The issue can leave an inode marked with DENT_BIT_SHIFT after it has already been checkpointed, which may be detected by fsck.

Linux kernel
Ubuntu
linux-ibm (Ubuntu package)
linux-azure (Ubuntu package)
linux-aws (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-nvidia-bos (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux-ibm (Ubuntu package) - addressed in versions 7.0.0-1008.8, 7.0.0-1010.10
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1010.10
linux-aws (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1015.15
linux-nvidia (Ubuntu package) - addressed in versions 7.0.0-1016.16, 7.0.0-1016.16~24.04.1
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2016.16

• https://git.kernel.org/stable/c/019f9dda7f66e55eb94cd32e1d3fff5835f73fbc
• https://git.kernel.org/stable/c/b28a83ea4934215b5de906c3ee4fbfbc651573e0
• https://git.kernel.org/stable/c/bedb710b63ae1bd617e65d0a8cf6cea1200b3753

• Race condition in Linux kernel f2fs
• Ubuntu update for linux-ibm
• Ubuntu update for linux-azure
• Ubuntu update for linux-aws
• Ubuntu update for linux-nvidia-bos
• Ubuntu update for linux-nvidia