{"id":"CVE-2026-98286","summary":"drop_monitor: use timer_shutdown_sync() to prevent timer rearming during teardown","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":"2026-10-08T02:52:56.438766582Z","published":"2026-10-06T08:45:47.167Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98286.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/9616b0c67fbd8cc0b49de7b26cdf2ab33747c80e"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bda4d9525fb91a2388ee09669421b8d505290864"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c391a40f71886b28c082b47270f0e856fa3e1150"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98286.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98286"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"9398e9c0b1d44eeb700e9e766c02bcc765c82570"},{"fixed":"9616b0c67fbd8cc0b49de7b26cdf2ab33747c80e"},{"fixed":"bda4d9525fb91a2388ee09669421b8d505290864"},{"fixed":"c391a40f71886b28c082b47270f0e856fa3e1150"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"5.10.27"},{"fixed":"5.11"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"5.11.11"},{"fixed":"5.12"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"2514c7ad115e762562c7bdd58bb1ab3425a98245"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"439b1164da3612ec7e186e1dc314471e7190bfc7"}]}],"versions":["v5.10.271","v5.10.270","v5.10.269","v5.10.268","v5.10.267","v5.10.266","v5.10.265","v5.10.264","v5.10.263","v5.10.262","v5.10.261","v5.10.260","v5.10.259","v5.10.258","v5.10.257","v5.10.256","v5.10.255","v5.10.254","v5.10.253","v5.10.252","v5.10.251","v5.10.250","v5.10.249","v5.10.248","v5.10.247","v5.10.246","v5.10.245","v5.10.244","v5.10.243","v5.10.242","v5.10.241","v5.10.240","v5.10.239","v5.10.238","v5.10.237","v5.10.236","v5.10.235","v5.10.234","v5.10.233","v5.10.232","v5.10.231","v5.10.230","v5.10.229","v5.10.228","v5.10.227","v5.10.226","v5.10.225","v5.10.224","v5.10.223","v5.10.222","v5.10.221","v5.10.220","v5.10.219","v5.10.218","v5.10.217","v5.10.216","v5.10.215","v5.10.214","v5.10.213","v5.10.212","v5.10.211","v5.10.210","v5.10.209","v5.10.208","v5.10.207","v5.10.206","v5.10.205","v5.10.204","v5.10.203","v5.10.202","v5.10.201","v5.10.200","v5.10.199","v5.10.198","v5.10.197","v5.10.196","v5.10.195","v5.10.194","v5.10.193","v5.10.192","v5.10.191","v5.10.190","v5.10.189","v5.10.188","v5.10.187","v5.10.186","v5.10.185","v5.10.184","v5.10.183","v5.10.182","v5.10.181","v5.10.180","v5.10.179","v5.10.178","v5.10.177","v5.10.176","v5.10.175","v5.10.174","v5.10.173","v5.10.172","v5.10.171","v5.10.170","v5.10.169","v5.10.168","v5.10.167","v5.10.166","v5.10.165","v5.10.164","v5.10.163","v5.10.162","v5.10.161","v5.10.160","v5.10.159","v5.10.158","v5.10.157","v5.10.156","v5.10.155","v5.10.154","v5.10.153","v5.10.152","v5.10.151","v5.10.150","v5.10.149","v5.10.148","v5.10.147","v5.10.146","v5.10.145","v5.10.144","v5.10.143","v5.10.142","v5.10.141","v5.10.140","v5.10.139","v5.10.138","v5.10.137","v5.10.136","v5.10.135","v5.10.134","v5.10.133","v5.10.132","v5.10.131","v5.10.130","v5.10.129","v5.10.128","v5.10.127","v5.10.126","v5.10.125","v5.10.124","v5.10.123","v5.10.122","v5.10.121","v5.10.120","v5.10.119","v5.10.118","v5.10.117","v5.10.116","v5.10.115","v5.10.114","v5.10.113","v5.10.112","v5.10.111","v5.10.110","v5.10.109","v5.10.108","v5.10.107","v5.10.106","v5.10.105","v5.10.104","v5.10.103","v5.10.102","v5.10.101","v5.10.100","v5.10.99","v5.10.98","v5.10.97","v5.10.96","v5.10.95","v5.10.94","v5.10.93","v5.10.92","v5.10.91","v5.10.90","v5.10.89","v5.10.88","v5.10.87","v5.10.86","v5.10.85","v5.10.84","v5.10.83","v5.10.82","v5.10.81","v5.10.80","v5.10.79","v5.10.78","v5.10.77","v5.10.76","v5.10.75","v5.10.74","v5.10.73","v5.10.72","v5.10.71","v5.10.70","v5.10.69","v5.10.68","v5.10.67","v5.10.66","v5.10.65","v5.10.64","v5.10.63","v5.10.62","v5.10.61","v5.10.60","v5.10.59","v5.10.58","v5.10.57","v5.10.56","v5.10.55","v5.10.54","v5.10.53","v5.10.52","v5.10.51","v5.10.50","v5.10.49","v5.10.48","v5.10.47","v5.10.46","v5.10.45","v5.10.44","v5.10.43","v5.10.42","v5.10.41","v5.10.40","v5.10.39","v5.10.38","v5.10.37","v5.10.36","v5.10.35","v5.10.34","v5.10.33","v5.10.32","v5.10.31","v5.10.30","v5.10.29","v5.10.28","v5.10.27","v5.11.22","v5.11.21","v5.11.20","v5.11.19","v5.11.18","v5.11.17","v5.11.16","v5.11.15","v5.11.14","v5.11.13","v5.11.12","v5.11.11"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98286.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced"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