kernel: RISC-V: KVM: Synchronize hrtimer callback during teardown (CVE-2026-98464)

Overview

A flaw was found in the Linux kernel's KVM (Kernel-based Virtual Machine) implementation for the RISC-V architecture. This vulnerability can lead to a Denial of Service (DoS) or host system crash due to a use-after-free memory issue during virtual machine teardown. A race condition allows a timer callback to continue executing after its associated virtual central processing unit (vCPU) has already been freed. A malicious user within a guest virtual machine can exploit this by scheduling a timer and immediately requesting a system shutdown.

Vendor advisories

• Red Hat VEX · Moderate · updated 2026-10-24 · vex

kernel: RISC-V: KVM: Synchronize hrtimer callback during teardown — rated Moderate by Red Hat. Released 2026-10-18, updated 2026-10-24.

Not affected:

• Red Hat Enterprise Linux 10
• Red Hat Enterprise Linux 6
• Red Hat Enterprise Linux 7
• Red Hat Enterprise Linux 8
• Red Hat Enterprise Linux 9
• Red Hat OpenShift Container Platform 4

Remediation

Refer to the advisory for fix availability.