Executive brief
A vulnerability exists in the Linux kernel's framebuffer console (fbcon) component, which manages how text is displayed on screens. A local user could trigger a system crash by exploiting a flaw where the system fails to properly handle errors during display initialization. This results in a 'NULL pointer dereference,' leading to a denial of service (system instability or crash).
Technical details
A NULL pointer dereference vulnerability exists in the Linux kernel's framebuffer console (fbcon) driver. The issue occurs in fbcon_init() when it calls con2fb_acquire_newinfo(). If the underlying fbcon_open() call fails within con2fb_acquire_newinfo(), the info->fbcon_par pointer remains NULL. Subsequent code dereferences this pointer without verifying its validity, leading to a kernel oops or crash. This is a local attack vector requiring low privileges. Patches have been released across multiple stable kernel branches to ensure the return value of con2fb_acquire_newinfo() is checked before proceeding.
Affected products
- Linux Linux kernel 2.6.23 to 5.15.203, 5.16 to 6.1.165, 6.2 to 6.6.128, 6.7 to 6.12.75, 6.13 to 6.18.16, 6.19 to 6.19.6
Timeline
- 2026-05-06: disclosed
- 2026-05-06: advisory
- 2026-02-14: patched: Initial patch committed to stable tree
References
- https://git.kernel.org/stable/c/011a0502801c8536f64141a2b61362c14f456544
- https://git.kernel.org/stable/c/0b038c0be6827dd2dbb1ce4f8d92d97c80cbe9cc
- https://git.kernel.org/stable/c/11a93180a70bb3095a9bd80d113d9277e30d9959
- https://git.kernel.org/stable/c/3b5a754ec86bc6064af9aca76eb191c2405e6b0c
- https://git.kernel.org/stable/c/a785c4e2a999c2d51dfcf40d317cfb30cc735d2c
- https://git.kernel.org/stable/c/d3e535533767c85788529e626478718b7e95a59f
- https://git.kernel.org/stable/c/f57b61624c86ef8f87f6e6b7dd0755de03d90e89