NULL pointer dereference in Linux kernel - CVE-2026-89835
Published: September 17, 2026
Vulnerability identifier: #VU150447
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-89835
CWE-ID: CWE-476
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to a null pointer dereference in the f2fs ckpt_thread_ioprio sysfs store path when writing the checkpoint thread I/O priority through sysfs while checkpoint merge is enabled and no checkpoint thread is running. A local user can write a checkpoint thread I/O priority value through sysfs to cause a denial of service.
A read-only mount is one condition in which no checkpoint merge thread is started.
Affected software
Linux kernel
How to mitigate CVE-2026-89835
Install security update from vendor's repository.
Linux kernel - update to 7.0 rc3