Linux Kernel up to 7.1.2 RCU kernel/irq_work.c stop_this_cpu use after free

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4.0	$0-$5k	0.00

Summaryinfo

A vulnerability categorized as problematic has been discovered in Linux Kernel up to 6.1.177/6.6.144/6.12.94/6.18.37/7.1.2. Impacted is the function stop_this_cpu of the file kernel/irq_work.c of the component RCU. The manipulation results in use after free. This vulnerability is reported as CVE-2026-64248. The attack requires a local approach. No exploit exists.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.1.177/6.6.144/6.12.94/6.18.37/7.1.2. It has been classified as problematic. Affected is the function stop_this_cpu of the file kernel/irq_work.c of the component RCU. The manipulation with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: MIPS: smp: report dying CPU to RCU in stop_this_cpu() smp_send_stop() parks all secondary CPUs in stop_this_cpu(). 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. Since commit 91840be8f710 ("irq_work: Fix use-after-free in irq_work_single() on PREEMPT_RT") however, irq_work_sync() calls synchronize_rcu() on architectures without an irq_work self-IPI, i.e. where arch_irq_work_has_interrupt() returns false. That is the asm-generic default used by MIPS. Any irq_work_sync() issued in the reboot/shutdown 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 was noticed on several Realtek MIPS switch SoCs (MIPS interAptiv) and came up during kernel bump downstream in OpenWrt from 6.18.33 to 6.18.34, after the backport of the patch to the 6.18 stable branch. The patch also has been backported all the way back to 6.1. 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. MIPS shuts down all CPUs here without going through the CPU-hotplug mechanism, so this report is not otherwise issued. Reporting a dying CPU to RCU outside the regular hotplug offline path is not unprecedented: arm64 does the same in cpu_die_early(). There it is an exception for a CPU that was coming online and is aborting bringup, rather than the default shutdown action as on MIPS.

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2026-64248 since 07/19/2026. The exploitability is told to be easy. The attack needs to be approached locally. Additional levels of successful authentication are required for exploitation. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available.

Upgrading to version 6.1.178, 6.6.145, 6.12.95, 6.18.38, 7.1.3 or 7.2-rc1 eliminates this vulnerability. Applying the patch f8a1ef884013dc99f712d3eb75624c7cd3fd94f6/e1919d026706544cb6e7251ec06e908edd6f34ee/6eda71977ee11c222f8ad4cae4d18d50448e56f4/f9b57a0015c241274651f4b36627f56b1b5a8651/9fef09df42df55ab819b285ea892e0fc1b95a9c4/9f3f3bdc6d9dac1a5a8262ee7ad0f2ff1527a7e7 is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.1.177
• 6.6.144
• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
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• 6.12.88
• 6.12.89
• 6.12.90
• 6.12.91
• 6.12.92
• 6.12.93
• 6.12.94
• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
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• 6.18.32
• 6.18.33
• 6.18.34
• 6.18.35
• 6.18.36
• 6.18.37
• 7.1.0
• 7.1.1
• 7.1.2

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔒
• 🔒
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CPE 2.2info

• 🔒
• 🔒
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CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.2
VulDB Meta Temp Score: 4.0

VulDB Base Score: 4.2
VulDB Temp Score: 4.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.1.178/6.6.145/6.12.95/6.18.38/7.1.3/7.2-rc1
Patch: f8a1ef884013dc99f712d3eb75624c7cd3fd94f6/e1919d026706544cb6e7251ec06e908edd6f34ee/6eda71977ee11c222f8ad4cae4d18d50448e56f4/f9b57a0015c241274651f4b36627f56b1b5a8651/9fef09df42df55ab819b285ea892e0fc1b95a9c4/9f3f3bdc6d9dac1a5a8262ee7ad0f2ff1527a7e7

Timelineinfo

07/19/2026 CVE reserved
07/24/2026 +5 days Advisory disclosed
07/24/2026 +0 days VulDB entry created
07/24/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-64248 (🔒)
GCVE (CVE): GCVE-0-2026-64248
GCVE (VulDB): GCVE-100-382992

Entryinfo

Created: 07/24/2026 19:30
Changes: 07/24/2026 19:30 (60)
Complete: 🔍
Cache ID: 216::103

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