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 when remove_on_exec removes an event. This preserves the existing task-exit and revoke behavior, while ensuring surviving siblings are ungrouped before the removed event leaves the context.

A flaw was found in the Linux kernel's performance monitoring unit (PMU) subsystem. This vulnerability occurs when a performance event group leader is removed during process execution, but its associated events (siblings) remain active and linked to a stale list. This inconsistent state can lead to a corruption of the PMU context active list, potentially causing system instability or a denial of service. A local attacker could potentially exploit this to disrupt system operations.

Red Hat Enterprise Linux 10 Affected kernel Red Hat Enterprise Linux 6 Under investigation kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Affected kernel Red Hat Enterprise Linux 8 Affected kernel-rt Red Hat Enterprise Linux 9 Affected kernel Red Hat Enterprise Linux 9 Affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-64556 https://nvd.nist.gov/vuln/detail/CVE-2026-64556 https://lore.kernel.org/linux-cve-announce/2026072939-CVE-2026-64556-0f2c@gregkh/T