{"id":"AZL-94139","summary":"CVE-2026-64556 affecting package kernel for versions less than 6.6.145.2-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nperf/core: Detach event groups during remove_on_exec\n\nperf_event_remove_on_exec() removes events by calling\nperf_event_exit_event(). For top-level events, this removes the event from\nthe context with DETACH_EXIT only.\n\nThis can leave inconsistent group state when a removed event is a group\nleader and the group contains siblings without remove_on_exec. If the group\nwas active, the surviving siblings can remain active and attached to the\nremoved leader's sibling list, but are no longer represented by a valid\ngroup leader on the PMU context active lists.\n\nA later close of the removed leader uses DETACH_GROUP and can promote the\nstill-active siblings from this stale group state. The next schedule-in can\nthen add an already-linked active_list entry again, corrupting the PMU\ncontext active list.\n\nWith DEBUG_LIST enabled, this is caught as a list_add double-add in\nmerge_sched_in().\n\nFix this by detaching group relationships when remove_on_exec removes an\nevent. This preserves the existing task-exit and revoke behavior, while\nensuring surviving siblings are ungrouped before the removed event leaves\nthe context.","modified":"2026-08-28T17:47:35.938365628Z","published":"2026-07-29T09:16:30Z","upstream":["CVE-2026-64556"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64556"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.145.2-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-94139.json"}}],"schema_version":"1.9.0"}