Linux Kernel Out-of-Bounds Read Vulnerability in fbcon Component

A vulnerability in the Linux kernel's framebuffer console (fbcon) component can lead to an out-of-bounds read and potential memory disclosure. This issue arises in the 'fbcon_do_set_font()' function when a memory allocation failure occurs during 'vc_resize()', causing the function to skip restoring the 'hi_font' state. As a result, the virtual terminal (VT) subsystem continues to accept character indices greater than 255 from userspace, which are then incorrectly mapped to the screen buffer. This desynchronization allows for accessing invalid memory regions, creating a risk of kernel memory disclosure.

Impact

Exploitation of this vulnerability causes a deterministic out-of-bounds read from the framebuffer console's font array, leading to unauthorized access to kernel memory, which could be exploited to disclose sensitive information or manipulate kernel operations.

Remediation

Users can upgrade to the patched version of the Linux kernel available in the Linux Kernel Archive.