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.
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).
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
| Date | Event | Detail |
| April 16, 2025 | Reserved | Reserved by Linux |
| May 20, 2025 | Published | Published (CNA: Linux) |
| July 30, 2026 | RESCORED | RESCORED — CVE-2025-37936 (Linux). CVSS 8.7 → 5.5 (NVD). |
Affected
Affected products and packages — 2 rows
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
| Linux | Linux | — | c59a1f106f5cd4843c097069ff1bb2ad72103a67 | — |
| Linux | Linux | — | 6.0 | 6.1.138 |
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.