CVE-2026-53403

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.

• linux linux kernel (>= 2.6.12.1 < 5.10.260) • linux linux kernel (>= 5.11 < 5.15.211) • linux linux kernel (>= 5.16 < 6.1.177) • linux linux kernel (>= 6.2 < 6.6.144) • linux linux kernel (>= 6.7 < 6.12.95) • linux linux kernel (>= 6.13 < 6.18.38) • linux linux kernel (>= 6.19 < 7.1.3) • linux linux kernel 2.6.12