CVE-2026-64556

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

perf/core: Detach event groups during remove_on_exec

perf_event_remove_on_exec() removes events by calling

perf_event_exit_event(). For top-level events, this removes the event from

the context with DETACH_EXIT only.

This can leave inconsistent group state when a removed event is a group

leader and the group contains siblings without remove_on_exec. If the group

was active, the surviving siblings can remain active and attached to the

removed leader's sibling list, but are no longer represented by a valid

group leader on the PMU context active lists.

A later close of the removed leader uses DETACH_GROUP and can promote the

still-active siblings from this stale group state. The next schedule-in can

then add an already-linked active_list entry again, corrupting the PMU

context active list.

With DEBUG_LIST enabled, this is caught as a list_add double-add in

merge_sched_in().

Fix this by detaching group relationships

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References