CVE-2026-98286
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: drop_monitor: use timer_shutdown_sync() to prevent timer rearming during teardown In drop_monitor teardown paths (net_dm_trace_off_set(), net_dm_hw_monitor_stop(), and error unwind paths in net_dm_trace_on_set() and net_dm_hw_monitor_start()), per-CPU timers are stopped using timer_delete_sync() followed by cancel_work_sync(). However, there is a circular dependency between send_timer and dm_alert_work: 1) sched_send_work() (timer callback) schedules dm_alert_work. 2) send_dm_alert() / net_dm_hw_summary_work() calls reset_per_cpu_data() or net_dm_hw_reset_per_cpu_data(). 3) If memory allocation fails under memory pressure in the reset function, it re-arms the timer via mod_timer(&data->send_timer, ...). If dm_alert_work is running concurrently while timer_delete_sync() executes on another CPU, an allocation failure in the worker will re-arm the timer after timer_delete_sync() has already returned. Once cancel_work_sync() completes and module_put() is called, the timer remains active in the timer wheel. If the module is then unloaded, the timer will fire and execute sched_send_work() in freed memory, triggering a kernel panic / use-after-free. Switch from timer_delete_sync() to timer_shutdown_sync(). This guarantees that any in-flight timer handler has finished and prevents subsequent re-arming attempts from running workers from succeeding. When monitoring is restarted later, timer_setup() is invoked, which cleanly re-initializes the timer.
View original CVE JSON
{
"id": "CVE-2026-98286",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-10-06T09:18:18.740",
"lastModified": "2026-10-19T10:18:30.170",
"vulnStatus": "Received",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "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->send_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."
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"net/core/drop_monitor.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "9398e9c0b1d44eeb700e9e766c02bcc765c82570",
"lessThan": "9616b0c67fbd8cc0b49de7b26cdf2ab33747c80e",
"versionType": "git",
"status": "affected"
},
{
"version": "9398e9c0b1d44eeb700e9e766c02bcc765c82570",
"lessThan": "bda4d9525fb91a2388ee09669421b8d505290864",
"versionType": "git",
"status": "affected"
},
{
"version": "9398e9c0b1d44eeb700e9e766c02bcc765c82570",
"lessThan": "c391a40f71886b28c082b47270f0e856fa3e1150",
"versionType": "git",
"status": "affected"
},
{
"version": "2514c7ad115e762562c7bdd58bb1ab3425a98245",
"versionType": "git",
"status": "affected"
},
{
"version": "439b1164da3612ec7e186e1dc314471e7190bfc7",
"versionType": "git",
"status": "affected"
},
{
"version": "5.10.27",
"lessThan": "5.11",
"versionType": "semver",
"status": "affected"
},
{
"version": "5.11.11",
"lessThan": "5.12",
"versionType": "semver",
"status": "affected"
}
]
},
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "affected",
"programFiles": [
"net/core/drop_monitor.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "5.12",
"status": "affected"
},
{
"version": "0",
"lessThan": "5.12",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.18.54",
"lessThanOrEqual": "6.18.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.2.8",
"lessThanOrEqual": "7.2.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.3",
"lessThanOrEqual": "*",
"versionType": "original_commit_for_fix",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {},
"references": [
{
"url": "https://git.kernel.org/stable/c/9616b0c67fbd8cc0b49de7b26cdf2ab33747c80e",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/bda4d9525fb91a2388ee09669421b8d505290864",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/c391a40f71886b28c082b47270f0e856fa3e1150",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
]
}