In the Linux kernel, the following vulnerability has been resolved:
fbdev: clear fb_info->mode before deleting a videomode
fb_set_var() can delete a mode from info->modelist when userspace
passes FB_ACTIVATE_INV_MODE through FBIOPUT_VSCREENINFO. 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 fb_info->mode.
fb_info->mode may still point into the modelist entry being deleted.
If the entry is freed, later mode sysfs reads through show_mode() can
dereference a stale pointer.
Clear fb_info->mode before calling fb_delete_videomode() when it
matches the mode being removed.