CVE-2022-50010: video: fbdev: i740fb: Check the argument of i740_calc_vclk()

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% 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: i740fb: Check the argument of i740_calc_vclk() 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. If the user provides an improper 'pixclock' value that makes the argumet of i740_calc_vclk() less than 'I740_RFREQ_FIX', it will cause a divide-by-zero bug in: drivers/video/fbdev/i740fb.c:353 p_best = min(15, ilog2(I740_MAX_VCO_FREQ / (freq / I740_RFREQ_FIX))); The following log can reveal it: divide error: 0000 [#1] PREEMPT SMP KASAN PTI RIP: 0010:i740_calc_vclk drivers/video/fbdev/i740fb.c:353 [inline] RIP: 0010:i740fb_decode_var drivers/video/fbdev/i740fb.c:646 [inline] RIP: 0010:i740fb_set_par+0x163f/0x3b70 drivers/video/fbdev/i740fb.c:742 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 i740_calc_vclk() first.

Affected products

Linux kernel: before 4.9.326; from 4.10 before 4.14.291; from 4.15 before 4.19.256; from 4.20 before 5.4.211; from 5.5 before 5.10.138; from 5.11 before 5.15.63 — fixed in 4.14.291, 4.19.256, 4.9.326, 5.10.138, 5.15.63, 5.19.4

How to fix

Upgrade to a fixed version: Linux kernel 4.14.291, 4.19.256, 4.9.326, 5.10.138. Check the vendor advisory for mitigations.

References

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