kernel: RISC-V: KVM: Fix PMU event info array size overflow (CVE-2026-89513)

Overview

A flaw was found in the Linux kernel's KVM (Kernel-based Virtual Machine) component for RISC-V architectures. A malicious guest operating system could exploit an integer overflow vulnerability by providing a crafted number of Performance Monitoring Unit (PMU) events during the SBI PMU EVENT_GET_INFO call. This leads to KVM allocating insufficient memory, resulting in out-of-bounds reads and writes. This memory corruption could allow a malicious guest to cause a denial of service (DoS) or potentially escalate privileges on the host system.

Vendor advisories

• Red Hat VEX · Moderate · updated 2026-09-18 · vex

kernel: RISC-V: KVM: Fix PMU event info array size overflow — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-18.

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.