CVE-2026-64513

Guest VM interruption via stale TPR threshold

Published Jul 25, 2026 · Updated Jul 25, 2026

Denial of service in Linux Kernel KVM x86 allows guest OS users to cause VM entry failures on affected virtualization hosts. When no interrupt is deliverable, apic_update_ppr() skips KVM_REQ_EVENT, leaving the VMCS TPR_THRESHOLD stale before VM entry. The failure requires older hardware or nested virtualization without virtual-interrupt delivery, and it interrupts the affected guest rather than the host.

CVSS severityUnavailable
Unscored
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Linux Kernel KVM x86 allows guest OS users to cause VM entry failures on affected virtualization hosts. When no interrupt is deliverable, apic_update_ppr() skips KVM_REQ_EVENT, leaving the VMCS TPR_THRESHOLD stale before VM entry. The failure requires older hardware or nested virtualization without virtual-interrupt delivery, and it interrupts the affected guest rather than the host.

The record

CVE
CVE-2026-64513
Published
Jul 25, 2026
Updated
Jul 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Jul 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 25, 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=4.11
  2. Affected versionversion=eb90f3417a0cc4880e979ccc84e41890d410ea5b <8c8e8ac22ee17d52f9eb2bc814bca7fab90fb8df
  3. Affected versionversion=eb90f3417a0cc4880e979ccc84e41890d410ea5b <bb365a506b1e6fb050c0fceaad354fe395385ef0
  4. Affected versionversion=eb90f3417a0cc4880e979ccc84e41890d410ea5b <ff9c4c6428883182960cfe5c78928f0896d80ebc

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linux Kernelversion=4.11; version=eb90f3417a0cc4880e979ccc84e41890d410ea5b <8c8e8ac22ee17d52f9eb2bc814bca7fab90fb8df; version=eb90f3417a0cc4880e979ccc84e41890d410ea5b <bb365a506b1e6fb050c0fceaad354fe395385ef0; version=eb90f3417a0cc4880e979ccc84e41890d410ea5b <ff9c4c6428883182960cfe5c78928f0896d80ebc

Published CVSS scores

No CVSS assessment is available in this record.

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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