CVE-2026-90305

Kernel faults via hard-IRQ timer locking

Published Sep 17, 2026 · Updated Sep 17, 2026

Incorrect timer locking in Linux 7.1 allows local users to trigger kernel faults via CPU timer expiry on ARM PREEMPT_RT systems. arch/arm/Kconfig omits HAVE_POSIX_CPU_TIMERS_TASK_WORK, leaving run_posix_cpu_timers() to acquire the sleeping sighand->siglock in hard IRQ context. The trigger requires a 32-bit ARM kernel with PREEMPT_RT enabled; the disclosure reports an invalid-context sleeping diagnostic, not a specific crash or hang.

CVSS severity6.8
Medium
EPSS probability0.20%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect timer locking in Linux 7.1 allows local users to trigger kernel faults via CPU timer expiry on ARM PREEMPT_RT systems. arch/arm/Kconfig omits HAVE_POSIX_CPU_TIMERS_TASK_WORK, leaving run_posix_cpu_timers() to acquire the sleeping sighand->siglock in hard IRQ context. The trigger requires a 32-bit ARM kernel with PREEMPT_RT enabled; the disclosure reports an invalid-context sleeping diagnostic, not a specific crash or hang.

The record

CVE
CVE-2026-90305
Published
Sep 17, 2026
Updated
Sep 17, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 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=7.1
  2. Affected versionversion=c6e61c06d6061750597e79c598acb5dead44c35b <8a58a41100ea377e978d99600ec24a9bd0273662
  3. Affected versionversion=c6e61c06d6061750597e79c598acb5dead44c35b <8de56782d6e5ba7a9f8c820342dccde65502f93f

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=7.1; version=c6e61c06d6061750597e79c598acb5dead44c35b <8a58a41100ea377e978d99600ec24a9bd0273662; version=c6e61c06d6061750597e79c598acb5dead44c35b <8de56782d6e5ba7a9f8c820342dccde65502f93f

Published CVSS scores

5.5SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
6.8SUSECVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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