Deadlock Affecting kernel6.18-tools-debuginfo package, versions <1:6.18.38-73.137.amzn2023
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applications- Snyk IDSNYK-AMZN2023-KERNEL618TOOLSDEBUGINFO-18905877
- published18 Aug 2026
- disclosed24 Jul 2026
Introduced: 24 Jul 2026
NewCVE-2026-64250 (opens in a new tab)How to fix?
Upgrade Amazon-Linux:2023 kernel6.18-tools-debuginfo to version 1:6.18.38-73.137.amzn2023 or higher.
This issue was patched in ALAS2023-2026-1969.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel6.18-tools-debuginfo package and not the kernel6.18-tools-debuginfo package as distributed by Amazon-Linux.
See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
LoongArch: Report dying CPU to RCU in stop_this_cpu()
This is a port of MIPS commit 9f3f3bdc6d9dac1 ("MIPS: smp: report dying CPU to RCU in stop_this_cpu()"). smp_send_stop() parks all secondary CPUs in stop_this_cpu(). And the function marks the CPU offline for the scheduler via set_cpu_online(false) but never informs RCU, so RCU keeps expecting a quiescent state from CPUs that are now spinning forever with interrupts disabled.
As long as nothing waits for an RCU grace period after smp_send_stop() this is harmless, which is why it went unnoticed. However, since commit 91840be8f710370 ("irq_work: Fix use-after-free in irq_work_single() on PREEMPT_RT"), irq_work_sync() calls synchronize_rcu() on architectures without an irq_work self-IPI, i.e. where arch_irq_work_has_interrupt() returns false. Any irq_work_sync() issued in the reboot/shutdown/halt path after smp_send_stop() then blocks on a grace period that can never complete, hanging the reboot:
WARNING: CPU: 0 PID: 15 at kernel/irq_work.c:144 irq_work_queue_on ... rcu: INFO: rcu_sched detected stalls on CPUs/tasks: rcu: Offline CPU 1 blocking current GP. rcu: Offline CPU 2 blocking current GP. rcu: Offline CPU 3 blocking current GP.
This issue needs some hacks to reproduce, and it was not noticed on LoongArch because arch_irq_work_has_interrupt() usually returns true.
Call rcutree_report_cpu_dead() once interrupts are disabled, mirroring the generic CPU-hotplug offline path, so RCU stops waiting on the parked CPUs and grace periods can still complete. LoongArch shuts down all CPUs here without going through the CPU-hotplug mechanism, so this report is not otherwise issued.
References
- http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-64250
- https://git.kernel.org/stable/c/0833b2b84c2fc1387f8165f0cbf6a02d67f647a5
- https://git.kernel.org/stable/c/1fa22de588a65880d6fe54c38c87fffe7d519f60
- https://git.kernel.org/stable/c/262dadc619e69ebeb97affd334cd1078a9704e98
- https://git.kernel.org/stable/c/90e254f18b8c224460082329dd5c42fd30995c2f
- https://git.kernel.org/stable/c/a0269e928728f970c782319fee53d92d4ea4e512
- https://git.kernel.org/stable/c/f2539c56c74691e7a88af6372ba2b48c06ed2fe4