---
id: CVE-2025-38215
title: >-
  fbdev: Fix do_register_framebuffer to prevent null-ptr-deref in
  fb_videomode_to_var
summary: >-
  In the Linux kernel, the following vulnerability has been resolved:


  fbdev: Fix do_register_framebuffer to prevent null-ptr-deref in
  fb_videomode_to_var


  If fb_add_videomode() in do_register_framebuffer() fails to allocate

  memory for fb_…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    908c5bb64f9c4319902b8ca1aa3fef8f83302520
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    0909b2b49c4546a7a08c80f53d93736b63270827
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    3f2098f4fba7718eb2501207ca6e99d22427f25a
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    d803c4c2a4ac8ce2be6d899d5c7ab0bf7ec355e9
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    17186f1f90d34fa701e4f14e6818305151637b9e
  - Linux 2.6.12
published: '2025-07-04'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T01:06:50.796Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2025-38215'
references:
  - url: 'https://git.kernel.org/stable/c/908c5bb64f9c4319902b8ca1aa3fef8f83302520'
  - url: 'https://git.kernel.org/stable/c/0909b2b49c4546a7a08c80f53d93736b63270827'
  - url: 'https://git.kernel.org/stable/c/3f2098f4fba7718eb2501207ca6e99d22427f25a'
  - url: 'https://git.kernel.org/stable/c/d803c4c2a4ac8ce2be6d899d5c7ab0bf7ec355e9'
  - url: 'https://git.kernel.org/stable/c/17186f1f90d34fa701e4f14e6818305151637b9e'
tags:
  - cve.org
epss: 0.00169
epssPercentile: 0.0622
ingestedAt: '2026-10-15T05:52:46.093Z'
---

## Overview

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

fbdev: Fix do_register_framebuffer to prevent null-ptr-deref in fb_videomode_to_var

If fb_add_videomode() in do_register_framebuffer() fails to allocate
memory for fb_videomode, it will later lead to a null-ptr dereference in
fb_videomode_to_var(), as the fb_info is registered while not having the
mode in modelist that is expected to be there, i.e. the one that is
described in fb_info->var.

================================================================
general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 1 PID: 30371 Comm: syz-executor.1 Not tainted 5.10.226-syzkaller #0
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
RIP: 0010:fb_videomode_to_var+0x24/0x610 drivers/video/fbdev/core/modedb.c:901
Call Trace:
 display_to_var+0x3a/0x7c0 drivers/video/fbdev/core/fbcon.c:929
 fbcon_resize+0x3e2/0x8f0 drivers/video/fbdev/core/fbcon.c:2071
 resize_screen drivers/tty/vt/vt.c:1176 [inline]
 vc_do_resize+0x53a/0x1170 drivers/tty/vt/vt.c:1263
 fbcon_modechanged+0x3ac/0x6e0 drivers/video/fbdev/core/fbcon.c:2720
 fbcon_update_vcs+0x43/0x60 drivers/video/fbdev/core/fbcon.c:2776
 do_fb_ioctl+0x6d2/0x740 drivers/video/fbdev/core/fbmem.c:1128
 fb_ioctl+0xe7/0x150 drivers/video/fbdev/core/fbmem.c:1203
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl fs/ioctl.c:739 [inline]
 __x64_sys_ioctl+0x19a/0x210 fs/ioctl.c:739
 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x67/0xd1
================================================================

Even though fbcon_init() checks beforehand if fb_match_mode() in
var_to_display() fails, it can not prevent the panic because fbcon_init()
does not return error code. Considering this and the comment in the code
about fb_match_mode() returning NULL - "This should not happen" - it is
better to prevent registering the fb_info if its mode was not set
successfully. Also move fb_add_videomode() closer to the beginning of
do_register_framebuffer() to avoid having to do the cleanup on fail.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

## Affected

- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 908c5bb64f9c4319902b8ca1aa3fef8f83302520`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 0909b2b49c4546a7a08c80f53d93736b63270827`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 3f2098f4fba7718eb2501207ca6e99d22427f25a`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < d803c4c2a4ac8ce2be6d899d5c7ab0bf7ec355e9`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 17186f1f90d34fa701e4f14e6818305151637b9e`
- `Linux 2.6.12`

## Remediation

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