SB2026032588 - Unchecked Return Value to NULL Pointer Dereference in Linux kernel block drbd driver

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Main Vulnerability Database SB2026032588

SB2026032588 - Unchecked Return Value to NULL Pointer Dereference in Linux kernel block drbd driver

Published: March 25, 2026

Security Bulletin ID SB2026032588
Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Local access
Highest impact Denial of service

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 security vulnerability.


1) Unchecked Return Value to NULL Pointer Dereference (CVE-ID: CVE-2026-23356)

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 update from vendor's website.

References