CVE-2022-50102: video: fbdev: arkfb: Fix a divide-by-zero bug in ark_set_pixclock()

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-06-18 · updated 2026-06-17
Weakness: CWE-369

Description

In the Linux kernel, the following vulnerability has been resolved: video: fbdev: arkfb: Fix a divide-by-zero bug in ark_set_pixclock() Since the user can control the arguments of the ioctl() from the user space, under special arguments that may result in a divide-by-zero bug in: drivers/video/fbdev/arkfb.c:784: ark_set_pixclock(info, (hdiv * info->var.pixclock) / hmul); with hdiv=1, pixclock=1 and hmul=2 you end up with (1*1)/2 = (int) 0. and then in: drivers/video/fbdev/arkfb.c:504: rv = dac_set_freq(par->dac, 0, 1000000000 / pixclock); we'll get a division-by-zero. The following log can reveal it: divide error: 0000 [#1] PREEMPT SMP KASAN PTI RIP: 0010:ark_set_pixclock drivers/video/fbdev/arkfb.c:504 [inline] RIP: 0010:arkfb_set_par+0x10fc/0x24c0 drivers/video/fbdev/arkfb.c:784 Call Trace: fb_set_var+0x604/0xeb0 drivers/video/fbdev/core/fbmem.c:1034 do_fb_ioctl+0x234/0x670 drivers/video/fbdev/core/fbmem.c:1110 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1189 Fix this by checking the argument of ark_set_pixclock() first.

Affected products

Linux kernel: from 2.6.22 before 4.14.291; from 4.15 before 4.19.256; from 4.20 before 5.4.211; from 5.5 before 5.10.137; from 5.11 before 5.15.61; from 5.16 before 5.18.18 — fixed in 4.14.291, 4.19.256, 5.10.137, 5.15.61, 5.18.18, 5.19.2

How to fix

Upgrade to a fixed version: Linux kernel 4.14.291, 4.19.256, 5.10.137, 5.15.61. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2022-50102 or the next vulnerability affects your stack