CVE-2026-99187

A flaw was found in the Linux kernel. During Central Processing Unit (CPU) hotplug operations, the Performance Monitoring Unit (PMU) context migration prematurely stops processing event groups after removing a leader, leaving active events running on the departing processor. A local user running performance monitoring events during CPU reconfiguration can trigger this flaw, leading to unexpected kernel behavior and potential system crashes that result in a Denial of Service (DoS).

This vulnerability is rated as having a Moderate impact because an attacker must possess local system access and coincide monitoring activity with runtime CPU hotplugging, limiting practical exploitability. On typical Red Hat Enterprise Linux deployments, dynamic processor offlining or addition is an infrequent administrative or virtualization event rather than a routine user-facing action. Although an incomplete event migration can trigger kernel instability or a denial of service, exploitation cannot be performed remotely and does not lead to privilege escalation or data confidentiality compromise.

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.