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Vulnerability · Published Feb 26, 2025 · Assigned by Linux

CVE-2021-47641video: fbdev: cirrusfb: check pixclock to avoid divide by zero

Medium 5.5

In plain English

A medium-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 17% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.5Medium
Exploit odds (30 days)0.3%top 83.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux5.17.3-1DEBIAN-CVE-2021-47641
Debian:13linux5.17.3-1DEBIAN-CVE-2021-47641
Debian:14linux5.17.3-1DEBIAN-CVE-2021-47641
Ubuntu:22.04:LTSlinux5.15.0-37.39UBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-aws5.15.0-1011.14UBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-azure5.15.0-1010.12UBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-gcp5.15.0-1008.12UBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-gke5.15.0-1008.10UBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-ibm5.15.0-1007.8UBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1008.11UBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-kvm5.15.0-1010.11UBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-37.39UBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-oracle5.15.0-1009.12UBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-raspi5.15.0-1011.13UBUNTU-CVE-2021-47641
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2021-47641
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2021-47641

Affected products (as reported)

VendorProductVersions
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before c656d04247a2654ede5cead2ecbf83431dad52611da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before 1d3fb46439ad4e8f0c5739eb33d1875ac9e0f1351da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before 40b13e3d85744210db13457785646634e2d056bd1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before 53a2088a396cfa1da92690a1da289634cd73bf0d1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before 8c7e2141fb89c620ab4e41512e262fbf25b8260d1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before 6fe23ff94e7840097202e85c148688940b37c9b11da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before 45800c42ef000f417270bcfc08630e42486fca991da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before e498b504f8c81b07efab9febf8503448de4dc9cf
Linux Linux 2.6.12

Weakness: CWE-369 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

References