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

Metrics

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Key SSVC decision points have not yet been added.

Affected Vendors & Products

Vendors Products
Linux
  • Linux Kernel

No data.

No data.

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

Mon, 23 Jun 2025 12:30:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Wed, 18 Jun 2025 11:15:00 +0000

Type Values Removed Values Added
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
Title fbdev: fb_pm2fb: Avoid potential divide by zero error
References
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-06-18T11:00:40.693Z

Reserved: 2025-06-18T10:57:27.385Z

Link: CVE-2022-49978

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-06-18T11:15:25.243

Modified: 2025-06-18T13:46:52.973

Link: CVE-2022-49978

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-06-18T00:00:00Z

Links: CVE-2022-49978 - Bugzilla