Linux Distros Unpatched Vulnerability : CVE-2026-64248

medium Nessus Plugin ID 329689

Synopsis

The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.

Description

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

- 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. (CVE-2026-64248)

Note that Nessus relies on the presence of the package as reported by the vendor.

Solution

There is no known solution at this time.

Plugin Details

Severity: Medium

ID: 329689

File Name: unpatched_CVE_2026_64248.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Misc.

Published: 7/25/2026

Updated: 7/25/2026

Supported Sensors: Agentless Assessment, Frictionless Assessment Agent, Nessus Agent, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.75

CVSS v2

Risk Factor: Medium

Base Score: 4.9

Temporal Score: 4.2

Vector: CVSS2#AV:L/AC:L/Au:N/C:N/I:N/A:C

CVSS Score Source: CVE-2026-64248

CVSS v3

Risk Factor: Medium

Base Score: 5.5

Temporal Score: 5.1

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:U/RC:C

Vulnerability Information

CPE: cpe:/o:debian:debian_linux:12.0, p-cpe:/a:debian:debian_linux:linux

Required KB Items: Host/cpu, Host/local_checks_enabled, global_settings/vendor_unpatched, Host/OS/identifier

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 7/24/2026

Reference Information

CVE: CVE-2026-64248

Detections

Analytics