CVE-2022-49978

In the Linux kernel, the following vulnerability has been resolved: fbdev: fb_pm2fb: Avoid potential divide by zero error In `do_fb_ioctl()` of fbmem.c, if cmd is FBIOPUT_VSCREENINFO, var will be copied from user, then go through `fb_set_var()` and `info->fbops->fb_check_var()` which could may be `pm2fb_check_var()`. Along the path, `var->pixclock` won't be modified. This function checks whether reciprocal of `var->pixclock` is too high. If `var->pixclock` is zero, there will be a divide by zero error. So, it is necessary to check whether denominator is zero to avoid crash. As this bug is found by Syzkaller, logs are listed below. divide error in pm2fb_check_var Call Trace: <TASK> fb_set_var+0x367/0xeb0 drivers/video/fbdev/core/fbmem.c:1015 do_fb_ioctl+0x234/0x670 drivers/video/fbdev/core/fbmem.c:1110 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1189

The following products are affected by CVE-2022-49978 vulnerability.

Here, you will find a curated list of external links that provide in-depth information to CVE-2022-49978.

URL	Resource
https://git.kernel.org/stable/c/0f1174f4972ea9fad6becf8881d71adca8e9ca91
https://git.kernel.org/stable/c/19f953e7435644b81332dd632ba1b2d80b1e37af
https://git.kernel.org/stable/c/34c3dea1189525cd533071ed5c176fc4ea8d982b
https://git.kernel.org/stable/c/3ec326a6a0d4667585ca595f438c7293e5ced7c4
https://git.kernel.org/stable/c/7d9591b32a9092fc6391a316b56e8016c6181c3d
https://git.kernel.org/stable/c/7f88cdfea8d7f4dbaf423d808241403b2bb945e4
https://git.kernel.org/stable/c/8fc778ee2fb2853f7a3531fa7273349640d8e4e9
https://git.kernel.org/stable/c/cb4bb011a683532841344ca7f281b5e04389b4f8
https://lore.kernel.org/linux-cve-announce/2025061820-CVE-2022-49978-8dc2@gregkh/T
https://nvd.nist.gov/vuln/detail/CVE-2022-49978
https://www.cve.org/CVERecord?id=CVE-2022-49978