CVE-2026-64374

A flaw was found in the Linux kernel's real-time (RT) scheduler. In non-real-time configurations, the RT_PUSH_IPI mechanism, designed to improve task migration, can lead to a live lock. This occurs when a CPU handling heavy network traffic is repeatedly interrupted by other CPUs attempting to schedule waiting real-time tasks. The continuous interruptions prevent the CPU from processing tasks, resulting in a Denial of Service (DoS) for that CPU.

This vulnerability is rated as Moderate impact because triggering the condition requires a specific concurrency scenario involving high softirq activity alongside real-time task scheduling, resulting in a localized denial of service rather than code execution or privilege escalation. Under non-PREEMPT_RT enterprise environments running multi-core systems, heavy workloads such as sustained network traffic can cause cross-CPU inter-processor interrupts to starve lower-priority execution threads and induce a live lock. Red Hat Enterprise Linux 8 kernels contain this scheduling mechanism, whereas releases such as Red Hat Enterprise Linux 9 and 10 are unaffected.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.