CVE-2021-47641: medium-severity vulnerability in Linux
video: fbdev: cirrusfb: check pixclock to avoid divide by zero
Published · Updated
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.5epss 0.3%
In the Linux kernel, the following vulnerability has been resolved:
video: fbdev: cirrusfb: check pixclock to avoid divide by zero
Do a sanity check on pixclock value to avoid divide by zero.
If the pixclock value is zero, the cirrusfb driver will round up
pixclock to get the derived frequency as close to maxclock as
possible.
Syzkaller reported a divide error in cirrusfb_check_pixclock.
divide error: 0000 [#1] SMP KASAN PTI
CPU: 0 PID: 14938 Comm: cirrusfb_test Not tainted 5.15.0-rc6 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2
RIP: 0010:cirrusfb_check_var+0x6f1/0x1260
Call Trace:
fb_set_var+0x398/0xf90
do_fb_ioctl+0x4b8/0x6f0
fb_ioctl+0xeb/0x130
__x64_sys_ioctl+0x19d/0x220
do_syscall_64+0x3a/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Affected products
Linux · LinuxRelated CVEs — Linux
In the same product, most dangerous first.
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References
https://git.kernel.org/stable/c/1d3fb46439ad4e8f0c5739eb33d1875ac9e0f135https://git.kernel.org/stable/c/40b13e3d85744210db13457785646634e2d056bdhttps://git.kernel.org/stable/c/45800c42ef000f417270bcfc08630e42486fca99https://git.kernel.org/stable/c/53a2088a396cfa1da92690a1da289634cd73bf0dhttps://git.kernel.org/stable/c/5c6f402bdcf9e7239c6bc7087eda71ac99b31379https://git.kernel.org/stable/c/6fe23ff94e7840097202e85c148688940b37c9b1https://git.kernel.org/stable/c/8c7e2141fb89c620ab4e41512e262fbf25b8260dhttps://git.kernel.org/stable/c/c656d04247a2654ede5cead2ecbf83431dad5261https://git.kernel.org/stable/c/e498b504f8c81b07efab9febf8503448de4dc9cf