CVE-2026-99105

Task stalls via missed local-queue rescheduling

Published Oct 28, 2026 · Updated Oct 28, 2026

A scheduling flaw in Linux sched_ext allows local users to stall runnable tasks when the CPU idles despite queued work. With SCX_OPS_ENQ_LAST, put_prev_task_scx() leaves a task on the CPU's local dispatch queue after selecting idle without requesting rescheduling. An active BPF scheduler with that flag is required; affected tasks wait for an unrelated wakeup or watchdog intervention, with exit_mmap() stalls exceeding 40 seconds reported during mass cgroup teardown.

CVSS severityUnavailable
Unscored
EPSS probability0.17%
Next 30 days · Nov 1, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A scheduling flaw in Linux sched_ext allows local users to stall runnable tasks when the CPU idles despite queued work. With SCX_OPS_ENQ_LAST, put_prev_task_scx() leaves a task on the CPU's local dispatch queue after selecting idle without requesting rescheduling. An active BPF scheduler with that flag is required; affected tasks wait for an unrelated wakeup or watchdog intervention, with exit_mmap() stalls exceeding 40 seconds reported during mass cgroup teardown.

The record

CVE
CVE-2026-99105
Published
Oct 28, 2026
Updated
Oct 28, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Oct 28, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 28, 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 <396ba6f04da3fd1fb5a3d1c9535bef3f967f4e59
  3. Affected versionversion=f0e1a0643a59bf1f922fa209cec86a170b784f3f <7a9df76679633cf26e0fea882a684012c6ec245a
  4. Affected versionversion=f0e1a0643a59bf1f922fa209cec86a170b784f3f <8d891c218016b6145993e082e7f732cb69dd0e29

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=6.12; version=f0e1a0643a59bf1f922fa209cec86a170b784f3f <396ba6f04da3fd1fb5a3d1c9535bef3f967f4e59; version=f0e1a0643a59bf1f922fa209cec86a170b784f3f <7a9df76679633cf26e0fea882a684012c6ec245a; version=f0e1a0643a59bf1f922fa209cec86a170b784f3f <8d891c218016b6145993e082e7f732cb69dd0e29

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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