CVE-2024-39483

Host panic via spurious NMI-state warning

Published Jul 5, 2024 · Updated Aug 5, 2026

Improper NMI-state handling in Linux KVM on AMD hosts allows guest OS users to panic the host by provoking simultaneous NMIs. The svm_enable_nmi_window() path warns whenever vNMI is enabled instead of only when the vCPU is already handling an NMI, so an STI shadow or GIF=0 produces a false warning while KVM continues correctly. Host interruption requires AMD SVM with vNMI and panic_on_warn=1; otherwise the event only logs a warning and taints the kernel.

CVSS severity7.4
High
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper NMI-state handling in Linux KVM on AMD hosts allows guest OS users to panic the host by provoking simultaneous NMIs. The svm_enable_nmi_window() path warns whenever vNMI is enabled instead of only when the vCPU is already handling an NMI, so an STI shadow or GIF=0 produces a false warning while KVM continues correctly. Host interruption requires AMD SVM with vNMI and panic_on_warn=1; otherwise the event only logs a warning and taints the kernel.

The record

CVE
CVE-2024-39483
Published
Jul 5, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 5, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=6.4
  2. Affected versionversion=fa4c027a7956f5e07697bfcb580d25eeb8471257 <1d87cf2eba46deaff6142366127f2323de9f84d1
  3. Affected versionversion=fa4c027a7956f5e07697bfcb580d25eeb8471257 <b4bd556467477420ee3a91fbcba73c579669edc6
  4. Affected versionversion=fa4c027a7956f5e07697bfcb580d25eeb8471257 <f79edaf7370986d73d204b36c50cc563a4c0f356

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.4; version=fa4c027a7956f5e07697bfcb580d25eeb8471257 <1d87cf2eba46deaff6142366127f2323de9f84d1; version=fa4c027a7956f5e07697bfcb580d25eeb8471257 <b4bd556467477420ee3a91fbcba73c579669edc6; version=fa4c027a7956f5e07697bfcb580d25eeb8471257 <f79edaf7370986d73d204b36c50cc563a4c0f356

Published CVSS scores

7.4kernel.orgCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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