#VU124485 Unchecked Return Value to NULL Pointer Dereference in Linux kernel - CVE-2026-23356
Published: March 25, 2026
Vulnerability identifier: #VU124485
Vulnerability risk: Low
CVSSv4.0: 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/E:U/U:Clear
CVE-ID: CVE-2026-23356
CWE-ID: CWE-690
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerable software:
Linux kernel
Linux kernel
Software vendor:
Linux Foundation
Linux Foundation
Description
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to improper handling of reference counting in the DRBD (Distributed Replicated Block Device) subsystem when processing I/O operations that cross activity log extent boundaries. A local user can trigger a sequence of I/O operations that result in an invalid reference count state, leading to a kernel BUG_ON condition and system crash.
The issue arises because the function drbd_al_begin_io_nonblock() may fail to acquire activity log references even when expected to succeed, yet continues execution without returning an error, resulting in inconsistent reference tracking during later I/O completion.
Remediation
Install security update from vendor's repository.
External links
- https://git.kernel.org/stable/c/7752569fc78e89794ce28946529850282233f99d
- https://git.kernel.org/stable/c/ab140365fb62c0bdab22b2f516aff563b2559e3b
- https://git.kernel.org/stable/c/d1ef3aed4df2ef1fe46befd8f2da9a6ec5445508
- https://git.kernel.org/stable/c/e91d8d6565b7819d13dab21d4dbed5b45efba59b
- https://git.kernel.org/stable/c/eef1390125b660b8b61f9f227a03bb9c5e6d36a5
- https://git.kernel.org/stable/c/f558e5404a72054b525dced1a0c66aa95a144153