CVE-2026-64070

Local task crash via leaked preempt count

Published Jul 19, 2026 · Updated Jul 19, 2026

Denial of service in Linux Kernel 6.6 through 7.0.10 allows local users to crash a task by repeatedly reading hv-gpci sysfs files. Four show callbacks in arch/powerpc/perf/hv-gpci.c call get_cpu_var(), which disables preemption, but omit put_cpu_var() after successful reads. On PowerPC systems with CONFIG_PREEMPT=y and exposed hv-gpci sysfs files, repeated reads leak the preempt count; the next user-mode page fault forces SIGSEGV, and its coredump triggers a scheduling-while-atomic kernel BUG.

CVSS severity7.1
High
EPSS probability0.12%
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 6.6 through 7.0.10 allows local users to crash a task by repeatedly reading hv-gpci sysfs files. Four show callbacks in arch/powerpc/perf/hv-gpci.c call get_cpu_var(), which disables preemption, but omit put_cpu_var() after successful reads. On PowerPC systems with CONFIG_PREEMPT=y and exposed hv-gpci sysfs files, repeated reads leak the preempt count; the next user-mode page fault forces SIGSEGV, and its coredump triggers a scheduling-while-atomic kernel BUG.

The record

CVE
CVE-2026-64070
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 19, 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=6.6
  2. Affected versionversion=71f1c39647d8c9d4d54a861ec81f1ff17544bcb6 <903409000a07ac8e31ffedeb8516f4f8d67150c8
  3. Affected versionversion=71f1c39647d8c9d4d54a861ec81f1ff17544bcb6 <dbc30a57bd8e026995e9fa8e8c31cffd18542c01

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.6; version=71f1c39647d8c9d4d54a861ec81f1ff17544bcb6 <903409000a07ac8e31ffedeb8516f4f8d67150c8; version=71f1c39647d8c9d4d54a861ec81f1ff17544bcb6 <dbc30a57bd8e026995e9fa8e8c31cffd18542c01

Published CVSS scores

6.6TenableAV:L/AC:L/Au:N/C:C/I:N/A:C
7.1TenableCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

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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