Tracker / CVE-2026-53403
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.
Affected products and versions
| linux | linux_kernel |
|---|---|
| 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 · 6.13 → 6.18.38 |
| linux | linux_kernel · 6.19 → 7.1.3 |
| linux | linux_kernel · 6.2 → 6.6.144 |
| linux | linux_kernel · 6.7 → 6.12.95 |