---
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: high
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
  - url: 'https://git.kernel.org/stable/c/cb016bcb40c81e7b19c4ae6143babb366dae8e20'
  - url: 'https://git.kernel.org/stable/c/ac562193c36696513ae196171892e9338475c4bc'
  - url: 'https://git.kernel.org/stable/c/3618a4c5b2591cfa83efe74f5b18c2d02b35c3f5'
  - url: 'https://git.kernel.org/stable/c/a7a526fbc847f07ad3a503c7382189be5ab68574'
tags:
  - nvd
  - cve.org
ingestedAt: '2026-07-19T23:34:10.558Z'
epss: 0.00171
epssPercentile: 0.06477
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 868749a7456dc48e93887a8474194e2ee6d6c21f <
    cb016bcb40c81e7b19c4ae6143babb366dae8e20
  - >-
    Linux >= ebd6f886aa2447fcfcdce5450c9e1028e1d681bb <
    ac562193c36696513ae196171892e9338475c4bc
  - >-
    Linux >= a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24 <
    3618a4c5b2591cfa83efe74f5b18c2d02b35c3f5
  - >-
    Linux >= a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24 <
    a7a526fbc847f07ad3a503c7382189be5ab68574
  - >-
    Linux >= a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24 <
    b5bb2c696e140c399cb874def2feedf61dee27d6
  - >-
    Linux >= a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24 <
    076b1aa65f77a49bce5a48a4a55a397cfcafa2b8
  - >-
    Linux >= a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24 <
    39815715cbcfabb16fc8c5f4a23deeda20f5df62
  - >-
    Linux >= a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24 <
    8fdc8c2057eea08d40ce2c8eed41ff9e451c65c2
  - Linux f08ccb792d3eaf1dc62d8cbf6a30d6522329f660
  - Linux >= 5.10.249 < 5.10.261
  - Linux >= 5.15.64 < 5.15.212
  - Linux >= 5.19.6 < 5.20
  - Linux 6.0
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H'
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-16T15:30:33.058892Z'
cvssSource: cna
---

## 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.