VulnerabilityPublished 17 Sep 2026Updated 23 Sep 2026

CVE-2026-90305: Linux kernel · ARM: 9483/1: select HAVE_POSIX_CPU_TIMERS_TASK_WORK

Affects Linux kernelSource GCVE Database

Not known to be exploited.

Data as of 26 Oct 2026, 13:47 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation evidence

Disclosed: evidence found.
CVE published 17 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Ubuntu 24.04 LTSlinux-aws-6.14`pkg:deb/ubuntu/linux-aws-6.14?arch=source&distro=noble`Other threats	Affected 6.14.0-1007.7~24.04.1 – 6.14.0-1018.18~24.04.1 11 affected builds	Fixed in–
Ubuntu 24.04 LTSlinux-aws-6.17`pkg:deb/ubuntu/linux-aws-6.17?arch=source&distro=noble`Other threats	Affected 6.17.0-1005.5~24.04.2 – 6.17.0-1020.20~24.04.1 10 affected builds	Fixed in–
Ubuntu 24.04 LTSlinux-azure-6.11`pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=noble`Other threats	Affected 6.11.0-1008.8~24.04.1 – 6.11.0-1018.18~24.04.1 7 affected builds	Fixed in–
Ubuntu 24.04 LTSlinux-azure-6.14`pkg:deb/ubuntu/linux-azure-6.14?arch=source&distro=noble`Other threats	Affected 6.14.0-1010.10~24.04.1 – 6.14.0-1017.17~24.04.1 5 affected builds	Fixed in–
Ubuntu 24.04 LTSlinux-azure-6.17`pkg:deb/ubuntu/linux-azure-6.17?arch=source&distro=noble`Other threats	Affected 6.17.0-1008.8~24.04.1 – 6.17.0-1022.22 10 affected builds	Fixed in–
Ubuntu 24.04 LTSlinux-azure-fde-6.14`pkg:deb/ubuntu/linux-azure-fde-6.14?arch=source&distro=noble`Other threats	Affected 6.14.0-1012.12~24.04.1 – 6.14.0-1017.17~24.04.1 5 affected builds	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available that selects HAVE_POSIX_CPU_TIMERS_TASK_WORK to defer CPU timer expiry to task context, resolving the invalid context bug. Users should apply the updated Linux kernel versions that include this fix. Patch status is confirmed by the resolution commit referenced in the description.

Description

A vulnerability in the Linux kernel ARM implementation was resolved by selecting HAVE_POSIX_CPU_TIMERS_TASK_WORK to defer POSIX CPU timer expiry to task context. Previously, CPU timers expired in hard IRQ context on PREEMPT_RT, causing a sleeping function to be called from an invalid context, which could lead to kernel bugs. This issue affects specific Linux kernel versions used in various Ubuntu LTS releases and linux-hwe-edge builds.

Impact

The vulnerability causes kernel bugs due to sleeping functions being called from invalid contexts, potentially leading to system instability or crashes on affected ARM Linux kernels with PREEMPT_RT enabled. It affects CPU timer expiry mechanisms, which are critical for process time accounting and timer-based operations.

Summary

The Linux kernel ARM vulnerability (CVE-2026-90305) involved the PREEMPT_RT patch enabling CPU timers to expire in hard IRQ context due to the lack of selection of HAVE_POSIX_CPU_TIMERS_TASK_WORK. This caused run_posix_cpu_timers() to call a sleeping function while holding a spinlock, triggering a BUG due to invalid context usage. The fix involved selecting HAVE_POSIX_CPU_TIMERS_TASK_WORK unconditionally (no longer conditional on KVM support) to defer CPU timer expiry to task context, preventing the invalid context bug. The issue was reproducible with setrlimit(RLIMIT_CPU, ...) and busy loops, affecting POSIX CPU timers and setitimer calls.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 24 Oct 2026, 22:26 UTC

Technical details

References

Community reviews

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