CyberRota Analysis
AI-GeneratedThe vulnerability affects the Linux kernel's framebuffer (fbdev) subsystem, specifically in the handling of framebuffer modes, which can lead to a null pointer dereference when the current mode does not match the updated modelist. This flaw can potentially cause system crashes or instability when the framebuffer is accessed, particularly during console operations. System administrators and developers managing Linux environments, especially those utilizing framebuffer consoles, should prioritize applying the relevant patches to mitigate this risk.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: fbdev: Fix fb_new_modelist to prevent null-ptr-deref in fb_videomode_to_var info->var, a framebuffer's current mode, is expected to have a matching entry in info->modelist. var_to_display() relies on this and treats a failed fb_match_mode() as "This should not happen". fb_set_var() keeps it true by adding the mode to the list on every change, and do_register_framebuffer() does the same at registration. store_modes() replaces the modelist from userspace. fb_new_modelist() validates the new modes but does not check that info->var still has a match. It relies on fbcon_new_modelist() to re-point consoles, but that only handles consoles mapped to the framebuffer. With fbcon unbound there are none, so info->var is left describing a mode that is no longer in the list. A later console takeover runs var_to_display(), where fb_match_mode() returns NULL and leaves fb_display[i].mode NULL. fbcon_switch() passes it to display_to_var(), and fb_videomode_to_var() dereferences the NULL mode. Keep the current mode in the list in fb_new_modelist(), the same way fb_set_var() does.
Related CVEs
Other vulnerabilities affecting the same vendor(s)