{"id":"AZL-106047","summary":"CVE-2026-98286 affecting package kernel 6.6.157.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrop_monitor: use timer_shutdown_sync() to prevent timer rearming during teardown\n\nIn drop_monitor teardown paths (net_dm_trace_off_set(),\nnet_dm_hw_monitor_stop(), and error unwind paths in net_dm_trace_on_set()\nand net_dm_hw_monitor_start()), per-CPU timers are stopped using\ntimer_delete_sync() followed by cancel_work_sync().\n\nHowever, there is a circular dependency between send_timer and\ndm_alert_work:\n1) sched_send_work() (timer callback) schedules dm_alert_work.\n2) send_dm_alert() / net_dm_hw_summary_work() calls reset_per_cpu_data()\n   or net_dm_hw_reset_per_cpu_data().\n3) If memory allocation fails under memory pressure in the reset\n   function, it re-arms the timer via mod_timer(&data-\u003esend_timer, ...).\n\nIf dm_alert_work is running concurrently while timer_delete_sync()\nexecutes on another CPU, an allocation failure in the worker will\nre-arm the timer after timer_delete_sync() has already returned.\nOnce cancel_work_sync() completes and module_put() is called, the timer\nremains active in the timer wheel. If the module is then unloaded, the\ntimer will fire and execute sched_send_work() in freed memory,\ntriggering a kernel panic / use-after-free.\n\nSwitch from timer_delete_sync() to timer_shutdown_sync(). This guarantees\nthat any in-flight timer handler has finished and prevents subsequent\nre-arming attempts from running workers from succeeding. When monitoring\nis restarted later, timer_setup() is invoked, which cleanly\nre-initializes the timer.","modified":"2026-10-07T14:16:54.757210741Z","published":"2026-10-06T09:18:18Z","upstream":["CVE-2026-98286"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98286"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.157.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-106047.json"}}],"schema_version":"1.9.0"}