CVE-2026-68421

Local denial of service via spurious scheduler warning

Published Aug 10, 2026 · Updated Aug 10, 2026

Improper consistency validation in Linux allows local users to interrupt service through a spurious sched_ext kernel warning. During a core-scheduling forced-idle transition, put_prev_task_scx() assumes balance_one() ran even though core_pick bypassed pick_task_scx(), then warns because SCX_OPS_ENQ_LAST is unset. Exploitation requires CONFIG_SCHED_CLASS_EXT and a core-scheduling cookie mismatch; the documented consequence is limited to availability.

CVSS severity5.5
Medium
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper consistency validation in Linux allows local users to interrupt service through a spurious sched_ext kernel warning. During a core-scheduling forced-idle transition, put_prev_task_scx() assumes balance_one() ran even though core_pick bypassed pick_task_scx(), then warns because SCX_OPS_ENQ_LAST is unset. Exploitation requires CONFIG_SCHED_CLASS_EXT and a core-scheduling cookie mismatch; the documented consequence is limited to availability.

The record

CVE
CVE-2026-68421
Published
Aug 10, 2026
Updated
Aug 10, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-1288, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

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=7c65ae81ea86a6ed8086e1a5651acd766187f19b <2907e9d0f05b506dfd58aec589a23042a56ef36b
  3. Affected versionversion=7c65ae81ea86a6ed8086e1a5651acd766187f19b <b7d9c359e5cf867f7eb23df3bb1c6b9e58af24da
  4. Affected versionversion=7c65ae81ea86a6ed8086e1a5651acd766187f19b <e2f188cdbf8312289532c36eb4e9eb1c9544d43a

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.12; version=7c65ae81ea86a6ed8086e1a5651acd766187f19b <2907e9d0f05b506dfd58aec589a23042a56ef36b; version=7c65ae81ea86a6ed8086e1a5651acd766187f19b <b7d9c359e5cf867f7eb23df3bb1c6b9e58af24da; version=7c65ae81ea86a6ed8086e1a5651acd766187f19b <e2f188cdbf8312289532c36eb4e9eb1c9544d43a

Published CVSS scores

5.5Red HatCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/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.

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1288Improper Validation of Consistency within Input
T1499.004Endpoint Denial of Service: Application 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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