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Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2025-37936MEDIUM
Linux Linux — perf/x86/intel: KVM: Mask PEBS_ENABLE loaded for guest with vCPU's value.
  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   L   L   L   N  U  N  N  H    5.5   .0019    8.4     —
AFFECTED
  Product  Versions                                    Fixed
  Linux    c59a1f106f5cd4843c097069ff1bb2ad72103a67 –  —
  Linux    6.0 –                                       6.1.138
TIMELINE
  Apr 16  Reserved by Linux
  May 20  Published (CNA: Linux)
  Jul 30  RESCORED — CVE-2025-37936 (Linux). CVSS 8.7 → 5.5 (NVD).
CNA: Linux · CVSS v3.1 · 6 references · NVD status: Modified

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 ("perf evlist: Remove __evlist__add_default") (after which, `perf kvm top` effectively stopped using PEBS). The userspace side of perf creates a guest-only PEBS event, which intel_guest_get_msrs() misconstrues a guest-*owned* PEBS event. Arguably, this is a userspace bug, as enabling PEBS on guest-only events simply cannot work, and userspace can kill VMs in many other ways (there is no danger to the host). However, even if this is considered to be bad userspace behavior, there's zero downside to perf/KVM restricting PEBS to guest-owned events. Note, commit 854250329c02 ("KVM: x86/pmu: Disable guest PEBS temporarily in two rare situations") fixed the case where host userspace is profiling KVM *and* userspace, but missed the case where userspace is profiling only KVM.

Lifecycle

Complete event history — 3 events, chronological
DateEventDetail
April 16, 2025ReservedReserved by Linux
May 20, 2025PublishedPublished (CNA: Linux)
July 30, 2026RESCOREDRESCORED — CVE-2025-37936 (Linux). CVSS 8.7 → 5.5 (NVD).

Affected

Affected products and packages — 2 rows
VendorProduct / PackageEcosystemVersion introducedFixed
LinuxLinuxc59a1f106f5cd4843c097069ff1bb2ad72103a67
LinuxLinux6.06.1.138

References (6)

Related

Authoritative record: CVE-2025-37936 at cve.org

Vendors: linux

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2025-37936 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.