In the Linux kernel, the following vulnerability has been resolved:
fbdev: Fix fb_set_var to prevent null-ptr-deref in fb_videomode_to_var
If fb_add_videomode() in fb_set_var() fails to allocate memory for
fb_videomode, later it may 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
================================================================
The reason is that fb_info->var is being modified in fb_set_var(), and
then fb_videomode_to_var() is called. If it fails to add the mode to
fb_info->modelist, fb_set_var() returns error, but does not restore the
old value of fb_info->var. Restore fb_info->var on failure the same way
it is done earlier in the function.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
References
Configurations
Configuration 1 (hide)
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Configuration 2 (hide)
|
History
18 Dec 2025, 21:10
| Type | Values Removed | Values Added |
|---|---|---|
| CPE | cpe:2.3:o:linux:linux_kernel:2.6.12:rc2:*:*:*:*:*:* cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:2.6.12:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:2.6.12:-:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:2.6.12:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:2.6.12:rc5:*:*:*:*:*:* |
|
| References | () https://git.kernel.org/stable/c/05f6e183879d9785a3cdf2f08a498bc31b7a20aa - Patch | |
| References | () https://git.kernel.org/stable/c/1a10d91766eb6ddfd5414e4785611e33a4fe0f9b - Patch | |
| References | () https://git.kernel.org/stable/c/3ca78032a388a0795201792b36e6fc9b6e6e8eed - Patch | |
| References | () https://git.kernel.org/stable/c/8a3a2887794b2c8e78b3e5d6e3de724527c9f41b - Patch | |
| References | () https://git.kernel.org/stable/c/b3071bb463ea1e6c686d0dc9638fc940f2f5cf17 - Patch | |
| References | () https://git.kernel.org/stable/c/ee20216f12d9482cd70e44dae5e7fabb38367c71 - Patch | |
| References | () https://git.kernel.org/stable/c/fab201d72fde38d081e2c5d4ad25595c535b7b22 - Patch | |
| References | () https://git.kernel.org/stable/c/ff0e037241173b574b385bff53d67567b9816db5 - Patch | |
| References | () https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html - Third Party Advisory, Mailing List | |
| References | () https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html - Third Party Advisory, Mailing List | |
| First Time |
Linux
Debian Debian debian Linux Linux linux Kernel |
|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 5.5 |
| CWE | CWE-476 |
03 Nov 2025, 18:16
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
08 Jul 2025, 16:18
| Type | Values Removed | Values Added |
|---|---|---|
| Summary |
|
04 Jul 2025, 14:15
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2025-07-04 14:15
Updated : 2025-12-18 21:10
NVD link : CVE-2025-38214
Mitre link : CVE-2025-38214
CVE.ORG link : CVE-2025-38214
JSON object : View
Products Affected
debian
- debian_linux
linux
- linux_kernel
CWE
CWE-476
NULL Pointer Dereference
