CVE-2025-37936

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

perf/x86/intel: KVM: Mask PEBS_ENABLE loaded for guest with vCPU's value.

When generating the MSR_IA32_PEBS_ENABLE value that will be loaded on

VM-Entry to a KVM guest, mask the value with the vCPU's desired PEBS_ENABLE

value. Consulting only the host kernel's host vs. guest masks results in

running the guest with PEBS enabled even when the guest doesn't want to use

PEBS. Because KVM uses perf events to proxy the guest virtual PMU, simply

looking at exclude_host can't differentiate between events created by host

userspace, and events created by KVM on behalf of the guest.

Running the guest with PEBS unexpectedly enabled typically manifests as

crashes due to a near-infinite stream of #PFs. E.g. if the guest hasn't

written MSR_IA32_DS_AREA, the CPU will hit page faults on address '0' when

trying to record PEBS events.

The issue is most easily reproduced by running `perf kvm top` from before

commit 7b100989b4f6 ("p

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References