CVE-2021-47641

video: fbdev: cirrusfb: check pixclock to avoid divide by zero

MEDIUM

5.5

CVSS Score

Published: February 26, 2025 at 01:54 AM UTC

Updated: June 17, 2026 at 04:18 AM UTC

1 product affected across 1 vendorLinux Kernel

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Severity

MEDIUM5.5

Exploit prediction

EPSS 0.3%

SSVC

No known exploit

Description

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

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Linux Kernel · Linux

95%

v < 4.9.3112.6.12 ≤ v < 4.14.2762.6.12 ≤ v < 4.19.2382.6.12 ≤ v < 4.9.3112.6.12 ≤ v < 5.10.1102.6.12 ≤ v < 5.15.332.6.12 ≤ v < 5.16.192.6.12 ≤ v < 5.17.22.6.12 ≤ v < 5.182.6.12 ≤ v < 5.4.1894.10 ≤ v < 4.14.2764.15 ≤ v < 4.19.2384.20 ≤ v < 5.4.1895.11 ≤ v < 5.15.335.16 ≤ v < 5.16.195.17 ≤ v < 5.17.25.5 ≤ v < 5.10.1101da177e4c3f41524e886b7f1b8a0c1fc7321cac2 2.6.12

Vendor states this is fixed in 1d3fb46439ad4e8f0c5739eb33d1875ac9e0f135 (fixed)

Vendor states this is fixed in 40b13e3d85744210db13457785646634e2d056bd (fixed)

Vendor states this is fixed in 45800c42ef000f417270bcfc08630e42486fca99 (fixed)

Vendor states this is fixed in 53a2088a396cfa1da92690a1da289634cd73bf0d (fixed)

Vendor states this is fixed in 5c6f402bdcf9e7239c6bc7087eda71ac99b31379 (fixed)

Vendor states this is fixed in 6fe23ff94e7840097202e85c148688940b37c9b1 (fixed)

Vendor states this is fixed in 8c7e2141fb89c620ab4e41512e262fbf25b8260d (fixed)

Vendor states this is fixed in c656d04247a2654ede5cead2ecbf83431dad5261 (fixed)

Vendor states this is fixed in e498b504f8c81b07efab9febf8503448de4dc9cf (fixed)

Vendor states this is fixed in 2.6.12 (unaffected)

Vendor states this is fixed in 4.14.276 (unaffected)

Vendor states this is fixed in 4.19.238 (unaffected)

Vendor states this is fixed in 4.9.311 (unaffected)

Vendor states this is fixed in 5.10.110 (unaffected)

Vendor states this is fixed in 5.15.33 (unaffected)

Vendor states this is fixed in 5.16.19 (unaffected)

Vendor states this is fixed in 5.17.2 (unaffected)

Vendor states this is fixed in 5.18 (unaffected)

Vendor states this is fixed in 5.4.189 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references