boxscore/security
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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-2024-39483MEDIUM
Linux Linux — KVM: SVM: WARN on vNMI + NMI window iff NMIs are outright masked
  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   L   L   L   N  U  N  N  H    5.5   .0023   13.6     —
AFFECTED
  Product  Versions                                    Fixed
  Linux    fa4c027a7956f5e07697bfcb580d25eeb8471257 –  —
  Linux    6.4 –                                       6.6.34
TIMELINE
  Jun 25  Reserved by Linux
  Jul 5   Published (CNA: Linux)
  Aug 4   RESCORED — CVE-2024-39483 (Linux). CVSS 7.1 → 5.5 (NVD).
CNA: Linux · CVSS v3.1 · 3 references · NVD status: Modified

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: WARN on vNMI + NMI window iff NMIs are outright masked When requesting an NMI window, WARN on vNMI support being enabled if and only if NMIs are actually masked, i.e. if the vCPU is already handling an NMI. KVM's ABI for NMIs that arrive simultanesouly (from KVM's point of view) is to inject one NMI and pend the other. When using vNMI, KVM pends the second NMI simply by setting V_NMI_PENDING, and lets the CPU do the rest (hardware automatically sets V_NMI_BLOCKING when an NMI is injected). However, if KVM can't immediately inject an NMI, e.g. because the vCPU is in an STI shadow or is running with GIF=0, then KVM will request an NMI window and trigger the WARN (but still function correctly). Whether or not the GIF=0 case makes sense is debatable, as the intent of KVM's behavior is to provide functionality that is as close to real hardware as possible. E.g. if two NMIs are sent in quick succession, the probability of both NMIs arriving in an STI shadow is infinitesimally low on real hardware, but significantly larger in a virtual environment, e.g. if the vCPU is preempted in the STI shadow. For GIF=0, the argument isn't as clear cut, because the window where two NMIs can collide is much larger in bare metal (though still small). That said, KVM should not have divergent behavior for the GIF=0 case based on whether or not vNMI support is enabled. And KVM has allowed simultaneous NMIs with GIF=0 for over a decade, since commit 7460fb4a3400 ("KVM: Fix simultaneous NMIs"). I.e. KVM's GIF=0 handling shouldn't be modified without a *really* good reason to do so, and if KVM's behavior were to be modified, it should be done irrespective of vNMI support.

Lifecycle

Complete event history — 3 events, chronological
DateEventDetail
June 25, 2024ReservedReserved by Linux
July 5, 2024PublishedPublished (CNA: Linux)
August 4, 2026RESCOREDRESCORED — CVE-2024-39483 (Linux). CVSS 7.1 → 5.5 (NVD).

Affected

Affected products and packages — 2 rows
VendorProduct / PackageEcosystemVersion introducedFixed
LinuxLinuxfa4c027a7956f5e07697bfcb580d25eeb8471257
LinuxLinux6.46.6.34

References (3)

Related

Authoritative record: CVE-2024-39483 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-2024-39483 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.