The Linux kernel framebuffer device (fbdev) bitblit functions bit_putcs_aligned() and bit_putcs_unaligned() improperly calculated glyph pointers by masking character values without ensuring the resulting index was within the font's glyph count. This allowed out-of-bounds reads past the built-in font array, a global memory safety issue. The vulnerability was fixed by clamping the glyph index to the actual glyph count before computing the address, eliminating the out-of-bounds read. This fix addresses a memory safety flaw reported by syzbot and prevents potential information disclosure or system instability caused by invalid memory reads.

The vulnerability allows a global out-of-bounds read in the Linux kernel framebuffer device code, which can lead to information disclosure or system instability. The CVSS vector indicates local attack vector with low complexity and low privileges required, no user interaction, unchanged scope, high confidentiality impact, no integrity impact, and high availability impact. No known exploits are reported in the wild.

A fix has been implemented in the Linux kernel to clamp the glyph index to the actual glyph count, preventing out-of-bounds reads. Users and administrators should apply the official Linux kernel updates that include this patch. Since this is a kernel-level vulnerability, updating to the fixed kernel version is the recommended remediation. Patch status is not explicitly confirmed in the provided data; check the vendor or Linux kernel advisory for the exact fixed version and update accordingly.