Linux Kernel Vulnerabilities: Insufficient Branch Predictor Isolation (VMSCAPE)

Researchers Jean-Claude Graf, Sandro Rüegge, Ali Hajiabadi, and Kaveh Razavi identified vulnerabilities in the Linux kernel related to insufficient branch predictor isolation between guest virtual machines (VMs) and userspace hypervisors on certain processors. This flaw, referred to as VMSCAPE (CVE-2025-40300), allows an attacker in a guest VM to potentially expose sensitive information from the host operating system. Multiple security issues were discovered that could compromise the system.