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Vulnerability · Published Jun 18, 2025 · Assigned by Linux

CVE-2022-49978fbdev: fb_pm2fb: Avoid potential divide by zero error

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 NVD)5.5Medium
Exploit odds (30 days)0.3%top 83.1% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official description

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

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux6.0.2-1DEBIAN-CVE-2022-49978
Debian:13linux6.0.2-1DEBIAN-CVE-2022-49978
Debian:14linux6.0.2-1DEBIAN-CVE-2022-49978
Ubuntu:22.04:LTSlinux5.15.0-57.63UBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-aws5.15.0-1027.31UBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-azure5.15.0-1030.37UBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1030.37.1UBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-gcp5.15.0-1026.33UBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-gke5.15.0-1024.29UBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1012.16UBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-ibm5.15.0-1022.25UBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1023.28UBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-kvm5.15.0-1025.30UBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-57.63UBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1015.15UBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-oracle5.15.0-1026.32UBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-raspi5.15.0-1022.24UBUNTU-CVE-2022-49978
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2022-49978
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2022-49978
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2022-49978
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2022-49978

Affected products (as reported)

VendorProductVersions
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before 0f1174f4972ea9fad6becf8881d71adca8e9ca911da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before 3ec326a6a0d4667585ca595f438c7293e5ced7c41da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before 7f88cdfea8d7f4dbaf423d808241403b2bb945e41da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before 7d9591b32a9092fc6391a316b56e8016c6181c3d1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before 8fc778ee2fb2853f7a3531fa7273349640d8e4e91da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before 34c3dea1189525cd533071ed5c176fc4ea8d982b1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before cb4bb011a683532841344ca7f281b5e04389b4f81da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before 19f953e7435644b81332dd632ba1b2d80b1e37af
Linux Linux 2.6.12

References