UBUNTU-CVE-2026-80579: High severity ubuntu/linux vulnerability
In the Linux kernel, the following vulnerability has been resolved: fbdev: clear fbinfo->mode before deleting a videomode fbsetvar() can delete a mode from info->modelist when userspace passes FBACTIVATEINVMODE through FBIOPUTVSCREENINFO. The code checks that the mode being deleted is not the current info->var and that fbcon is not using it, but it does not check fbinfo->mode. fbinfo->mode may still point into the modelist entry being deleted. If the entry is freed, later mode sysfs reads through showmode() can dereference a stale pointer. Clear fbinfo->mode before calling fbdeletevideomode() when it matches the mode being removed.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
ubuntu/linux-nvidia-tegrato a version that resolves this vulnerability.Fixed in 6.8.0-1036.39 - Configuration
Clear fb_info->mode before deleting a videomode to prevent later show_mode() sysfs reads from dereferencing a stale pointer.
Linux kernel fbdev fb_info->mode = clear before calling fb_delete_videomode() when it matches the mode being removed