CVE-2025-68195

In the Linux kernel, the function x86_match_min_microcode_rev() on a Zen5 CPU triggers an out-of-bounds access because the array zen5_rdseed_microcode lacks a proper terminator [1]. This omission allows the comparison loop to continue past the intended entries, reading beyond the array boundary.

An attacker with local access or the ability to trigger microcode version checks on affected Zen5 systems could exploit this to cause a kernel panic or potentially leverage the out-of-bounds read for information disclosure [1]. The bug manifests during CPU microcode revision matching, a routine operation performed by the kernel.

The impact is rated with a CVSS 7.8 high severity, as it could lead to a denial of service or exposure of sensitive kernel memory [1]. No public exploit code is known, but the out-of-bounds condition is readily reproducible.

A fix has been merged into the stable kernel tree via commit f1fdffe0afea02ba783acfe815b6a60e7180df40 [1]. Users of Zen5 CPUs are advised to apply the latest kernel updates to mitigate this vulnerability.