---
id: CVE-2026-53402
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  fbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font()

  When fbcon_do_set_font() fails (e.g., due to a memory allocation failure
  inside vc_resize() unde…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  fbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font()

  When fbcon_do_set_font() fails (e.g., due to a memory allocation failure
  inside vc_resize() unde…
severity: none
published: '2026-07-19'
updated: '2026-07-19'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-53402'
references:
  - url: 'https://git.kernel.org/stable/c/076b1aa65f77a49bce5a48a4a55a397cfcafa2b8'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/39815715cbcfabb16fc8c5f4a23deeda20f5df62'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8fdc8c2057eea08d40ce2c8eed41ff9e451c65c2'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b5bb2c696e140c399cb874def2feedf61dee27d6'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
ingestedAt: '2026-07-19T23:34:10.558Z'
epss: 0.00135
epssPercentile: 0.02427
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

fbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font()

When fbcon_do_set_font() fails (e.g., due to a memory allocation failure
inside vc_resize() under heavy memory pressure), it jumps to the `err_out`
label to roll back the console state. However, the current rollback logic
forgets to restore the `hi_font` state, leading to a severe state machine
corruption.

Earlier in the function, `set_vc_hi_font()` might be called to change
`vc->vc_hi_font_mask` and mutate the screen buffer. If `vc_resize()`
subsequently fails, the `err_out` path restores `vc_font.charcount`
but entirely skips rolling back the `vc_hi_font_mask` and the screen
buffer.

This mismatch leaves the terminal in a desynchronized state. Because
`vc_hi_font_mask` remains set, the VT subsystem will still accept
character indices greater than 255 from userspace and write them to the
screen buffer. Subsequent rendering calls (e.g., `fbcon_putcs()`) will
then use these inflated indices to access the reverted, 256-character
font array, leading to a deterministic out-of-bounds read and potential
kernel memory disclosure.

Fix this by adding the missing rollback logic for the `hi_font` mask
and screen buffer in the error path.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.