CVE-2026-23106

System disruption via wrong timekeeper leap-state update

Published Feb 4, 2026 · Updated Feb 4, 2026

Timekeeping flaw in Linux Kernel 6.17 through 6.18.7 and 6.19-rc1 through 6.19-rc6 allows local users to disrupt system availability. In __do_ajdtimex(), an auxiliary-clock request updates the global tk_core leap state instead of the selected timekeeper, writing its sequence lock without the matching spinlock. Triggering the faulty write requires an adjustable auxiliary clock and CAP_SYS_TIME, and the documented consequence is incorrect core timekeeping with a lock-debugging warning.

CVSS severity5.5
Medium
EPSS probability0.10%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Timekeeping flaw in Linux Kernel 6.17 through 6.18.7 and 6.19-rc1 through 6.19-rc6 allows local users to disrupt system availability. In __do_ajdtimex(), an auxiliary-clock request updates the global tk_core leap state instead of the selected timekeeper, writing its sequence lock without the matching spinlock. Triggering the faulty write requires an adjustable auxiliary clock and CAP_SYS_TIME, and the documented consequence is incorrect core timekeeping with a lock-debugging warning.

The record

CVE
CVE-2026-23106
Published
Feb 4, 2026
Updated
Feb 4, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Feb 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 4, 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=6.17
  2. Affected versionversion=775f71ebedd382da390dc16a4c28cffa5b937f79 <8f7c9dbeaa0be5810e44d323735967d3dba9239d
  3. Affected versionversion=775f71ebedd382da390dc16a4c28cffa5b937f79 <e806f7dde8ba28bc72a7a0898589cac79f6362ac

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.17; version=775f71ebedd382da390dc16a4c28cffa5b937f79 <8f7c9dbeaa0be5810e44d323735967d3dba9239d; version=775f71ebedd382da390dc16a4c28cffa5b937f79 <e806f7dde8ba28bc72a7a0898589cac79f6362ac

Published CVSS scores

5.5NIST NVDCVSS: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.

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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
Privilegesadmin
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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