SB2026072139 - NULL pointer dereference in Linux kernel fbdev core driver

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Main Vulnerability Database SB2026072139

SB2026072139 - NULL pointer dereference in Linux kernel fbdev core driver

Published: July 21, 2026

Security Bulletin ID SB2026072139
CSH 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 vulnerability.


1) NULL pointer dereference (CVE-ID: CVE-2026-53403)

CWE-ID: CWE-476 - NULL Pointer Dereference

CVSSv4: 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]


The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a null pointer dereference in fb_videomode_to_var in the fbdev subsystem when processing a userspace-supplied modelist that does not contain the current framebuffer mode. A local user can supply a crafted mode list to trigger a kernel crash and cause a denial of service.

Exploitation requires fbcon to be unbound so that the current mode is left without a matching entry before a later console takeover occurs.


Remediation

Install update from vendor's website.

References