SB20260824193 - Out-of-bounds read in Linux kernel fbdev core driver

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Main Vulnerability Database SB20260824193

SB20260824193 - Out-of-bounds read in Linux kernel fbdev core driver

Published: August 24, 2026

Security Bulletin ID SB20260824193
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Local access
Highest impact Information disclosure

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Out-of-bounds read (CVE-ID: CVE-2026-74635)

CWE-ID: CWE-125 - Out-of-bounds read

CVSSv4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a local user to disclose sensitive information.

The vulnerability exists due to an out-of-bounds read in the bit_cursor() function in drivers/video/fbdev/core/bitblit.c when processing screen buffer values as glyph indexes. A local user can write an arbitrary 16-bit value to /dev/vcsa to disclose sensitive information.

The issue can also be triggered when stale screen buffer data retains high-bit characters after switching from a 512-glyph font to a 256-glyph font.


Remediation

Install update from vendor's website.

References