CVE-2026-99085

CPU-offline hang via stranded BPF-scheduled tasks

Published Oct 23, 2026 · Updated Oct 23, 2026

A CPU-offline hang in Linux sched_ext allows attackers to stall CPU hotplug when a BPF scheduler retains runnable tasks. The CPU stops calling ops.dispatch() before its runqueue goes offline, leaving queued tasks unable to trigger balance_push() and wake the hotplug thread. Exposure requires a running BPF scheduler and CPU offlining with retained tasks; the operation hangs while holding cpu_hotplug_lock or stalls until the watchdog ejects the scheduler.

CVSS severityUnavailable
Unscored
EPSS probability0.16%
Next 30 days · Nov 1, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A CPU-offline hang in Linux sched_ext allows attackers to stall CPU hotplug when a BPF scheduler retains runnable tasks. The CPU stops calling ops.dispatch() before its runqueue goes offline, leaving queued tasks unable to trigger balance_push() and wake the hotplug thread. Exposure requires a running BPF scheduler and CPU offlining with retained tasks; the operation hangs while holding cpu_hotplug_lock or stalls until the watchdog ejects the scheduler.

The record

CVE
CVE-2026-99085
Published
Oct 23, 2026
Updated
Oct 23, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Oct 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 23, 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=6.12
  2. Affected versionversion=f0e1a0643a59bf1f922fa209cec86a170b784f3f <173ff9d03ec6373c3158b6e630af33a9b36fd216
  3. Affected versionversion=f0e1a0643a59bf1f922fa209cec86a170b784f3f <638ee6bca19750934ea13f9c325f46fd8ae60064
  4. Affected versionversion=f0e1a0643a59bf1f922fa209cec86a170b784f3f <d35a535d3e3e71f92a051d94e415f43612c4edfc
  5. Affected versionversion=f0e1a0643a59bf1f922fa209cec86a170b784f3f <f79cd7a2df3768323fbfb9b0f96adff08fb7eb4c

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=6.12; version=f0e1a0643a59bf1f922fa209cec86a170b784f3f <173ff9d03ec6373c3158b6e630af33a9b36fd216; version=f0e1a0643a59bf1f922fa209cec86a170b784f3f <638ee6bca19750934ea13f9c325f46fd8ae60064; version=f0e1a0643a59bf1f922fa209cec86a170b784f3f <d35a535d3e3e71f92a051d94e415f43612c4edfc; version=f0e1a0643a59bf1f922fa209cec86a170b784f3f <f79cd7a2df3768323fbfb9b0f96adff08fb7eb4c

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.

Activity data is delayed. The latest report is Sep 28, 2026.

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

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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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