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CVE-2025-38214: fbdev: Fix fb_set_var to prevent null-ptr-deref in fb_videomode_to_var

Description

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]
__s...

Classification

CVE ID: CVE-2025-38214

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.03% (probability of being exploited)

EPSS Percentile: 7.52% (scored less or equal to compared to others)

EPSS Date: 2025-07-10 (when was this score calculated)

References

https://nvd.nist.gov/vuln/detail/CVE-2025-38214
https://git.kernel.org/stable/c/ee20216f12d9482cd70e44dae5e7fabb38367c71
https://git.kernel.org/stable/c/fab201d72fde38d081e2c5d4ad25595c535b7b22
https://git.kernel.org/stable/c/1a10d91766eb6ddfd5414e4785611e33a4fe0f9b
https://git.kernel.org/stable/c/ff0e037241173b574b385bff53d67567b9816db5
https://git.kernel.org/stable/c/3ca78032a388a0795201792b36e6fc9b6e6e8eed
https://git.kernel.org/stable/c/b3071bb463ea1e6c686d0dc9638fc940f2f5cf17
https://git.kernel.org/stable/c/8a3a2887794b2c8e78b3e5d6e3de724527c9f41b
https://git.kernel.org/stable/c/05f6e183879d9785a3cdf2f08a498bc31b7a20aa

Timeline