PowerPC Kernel Vulnerability in User Mode Memory Restoration

CVE-2026-98396

What is CVE-2026-98396?

A vulnerability in the Linux kernel affects the PowerPC architecture, where the kernel improperly restores the user Address Mask Register (AMR) too early during user mode transitions. This flaw occurs specifically in the execution of the arch_exit_to_user_mode_prepare() function, which is incorrectly triggered before the necessary platform-specific exit routines are complete. Such early restoration can lead to exceptions and system instability, particularly under the conditions defined by the CONFIG_PPC_KUAP_DEBUG. Proper handling of user memory access is crucial to maintain system integrity and security.

References