CVE-2026-23192 - Vulnerability Details

Vendors	Products
Linux	Linux Kernel

Link	Providers
https://git.kernel.org/stable/c/2718ae6af7445ba2ee0abf6365ca43a9a3b16aeb
https://git.kernel.org/stable/c/83b67cc9be9223183caf91826d9c194d7fb128fa

Type	Values Removed	Values Added
Description		In the Linux kernel, the following vulnerability has been resolved: linkwatch: use __dev_put() in callers to prevent UAF After linkwatch_do_dev() calls __dev_put() to release the linkwatch reference, the device refcount may drop to 1. At this point, netdev_run_todo() can proceed (since linkwatch_sync_dev() sees an empty list and returns without blocking), wait for the refcount to become 1 via netdev_wait_allrefs_any(), and then free the device via kobject_put(). This creates a use-after-free when __linkwatch_run_queue() tries to call netdev_unlock_ops() on the already-freed device. Note that adding netdev_lock_ops()/netdev_unlock_ops() pair in netdev_run_todo() before kobject_put() would not work, because netdev_lock_ops() is conditional - it only locks when netdev_need_ops_lock() returns true. If the device doesn't require ops_lock, linkwatch won't hold any lock, and netdev_run_todo() acquiring the lock won't provide synchronization. Fix this by moving __dev_put() from linkwatch_do_dev() to its callers. The device reference logically pairs with de-listing the device, so it's reasonable for the caller that did the de-listing to release it. This allows placing __dev_put() after all device accesses are complete, preventing UAF. The bug can be reproduced by adding mdelay(2000) after linkwatch_do_dev() in __linkwatch_run_queue(), then running: ip tuntap add mode tun name tun_test ip link set tun_test up ip link set tun_test carrier off ip link set tun_test carrier on sleep 0.5 ip tuntap del mode tun name tun_test KASAN report: ================================================================== BUG: KASAN: use-after-free in netdev_need_ops_lock include/net/netdev_lock.h:33 [inline] BUG: KASAN: use-after-free in netdev_unlock_ops include/net/netdev_lock.h:47 [inline] BUG: KASAN: use-after-free in __linkwatch_run_queue+0x865/0x8a0 net/core/link_watch.c:245 Read of size 8 at addr ffff88804de5c008 by task kworker/u32:10/8123 CPU: 0 UID: 0 PID: 8123 Comm: kworker/u32:10 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Workqueue: events_unbound linkwatch_event Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x156/0x4c9 mm/kasan/report.c:482 kasan_report+0xdf/0x1a0 mm/kasan/report.c:595 netdev_need_ops_lock include/net/netdev_lock.h:33 [inline] netdev_unlock_ops include/net/netdev_lock.h:47 [inline] __linkwatch_run_queue+0x865/0x8a0 net/core/link_watch.c:245 linkwatch_event+0x8f/0xc0 net/core/link_watch.c:304 process_one_work+0x9c2/0x1840 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x5da/0xe40 kernel/workqueue.c:3421 kthread+0x3b3/0x730 kernel/kthread.c:463 ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 </TASK> ==================================================================
Title		linkwatch: use __dev_put() in callers to prevent UAF
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/2718ae6af7445ba2ee0abf6365ca43a9a3b16aeb https://git.kernel.org/stable/c/83b67cc9be9223183caf91826d9c194d7fb128fa

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-23192", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-01-13T15:37:45.985Z", "datePublished": "2026-02-14T16:27:19.557Z", "dateUpdated": "2026-02-14T16:27:19.557Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-02-14T16:27:19.557Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nlinkwatch: use __dev_put() in callers to prevent UAF\n\nAfter linkwatch_do_dev() calls __dev_put() to release the linkwatch\nreference, the device refcount may drop to 1. At this point,\nnetdev_run_todo() can proceed (since linkwatch_sync_dev() sees an\nempty list and returns without blocking), wait for the refcount to\nbecome 1 via netdev_wait_allrefs_any(), and then free the device\nvia kobject_put().\n\nThis creates a use-after-free when __linkwatch_run_queue() tries to\ncall netdev_unlock_ops() on the already-freed device.\n\nNote that adding netdev_lock_ops()/netdev_unlock_ops() pair in\nnetdev_run_todo() before kobject_put() would not work, because\nnetdev_lock_ops() is conditional - it only locks when\nnetdev_need_ops_lock() returns true. If the device doesn't require\nops_lock, linkwatch won't hold any lock, and netdev_run_todo()\nacquiring the lock won't provide synchronization.\n\nFix this by moving __dev_put() from linkwatch_do_dev() to its\ncallers. The device reference logically pairs with de-listing the\ndevice, so it's reasonable for the caller that did the de-listing\nto release it. This allows placing __dev_put() after all device\naccesses are complete, preventing UAF.\n\nThe bug can be reproduced by adding mdelay(2000) after\nlinkwatch_do_dev() in __linkwatch_run_queue(), then running:\n\n ip tuntap add mode tun name tun_test\n ip link set tun_test up\n ip link set tun_test carrier off\n ip link set tun_test carrier on\n sleep 0.5\n ip tuntap del mode tun name tun_test\n\nKASAN report:\n\n ==================================================================\n BUG: KASAN: use-after-free in netdev_need_ops_lock include/net/netdev_lock.h:33 [inline]\n BUG: KASAN: use-after-free in netdev_unlock_ops include/net/netdev_lock.h:47 [inline]\n BUG: KASAN: use-after-free in __linkwatch_run_queue+0x865/0x8a0 net/core/link_watch.c:245\n Read of size 8 at addr ffff88804de5c008 by task kworker/u32:10/8123\n\n CPU: 0 UID: 0 PID: 8123 Comm: kworker/u32:10 Not tainted syzkaller #0 PREEMPT(full)\n Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\n Workqueue: events_unbound linkwatch_event\n Call Trace:\n <TASK>\n __dump_stack lib/dump_stack.c:94 [inline]\n dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120\n print_address_description mm/kasan/report.c:378 [inline]\n print_report+0x156/0x4c9 mm/kasan/report.c:482\n kasan_report+0xdf/0x1a0 mm/kasan/report.c:595\n netdev_need_ops_lock include/net/netdev_lock.h:33 [inline]\n netdev_unlock_ops include/net/netdev_lock.h:47 [inline]\n __linkwatch_run_queue+0x865/0x8a0 net/core/link_watch.c:245\n linkwatch_event+0x8f/0xc0 net/core/link_watch.c:304\n process_one_work+0x9c2/0x1840 kernel/workqueue.c:3257\n process_scheduled_works kernel/workqueue.c:3340 [inline]\n worker_thread+0x5da/0xe40 kernel/workqueue.c:3421\n kthread+0x3b3/0x730 kernel/kthread.c:463\n ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158\n ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246\n </TASK>\n =================================================================="}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/core/link_watch.c"], "versions": [{"version": "04efcee6ef8d0f01eef495db047e7216d6e6e38f", "lessThan": "2718ae6af7445ba2ee0abf6365ca43a9a3b16aeb", "status": "affected", "versionType": "git"}, {"version": "04efcee6ef8d0f01eef495db047e7216d6e6e38f", "lessThan": "83b67cc9be9223183caf91826d9c194d7fb128fa", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/core/link_watch.c"], "versions": [{"version": "6.15", "status": "affected"}, {"version": "0", "lessThan": "6.15", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.10", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.19", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "6.18.10"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "6.19"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/2718ae6af7445ba2ee0abf6365ca43a9a3b16aeb"}, {"url": "https://git.kernel.org/stable/c/83b67cc9be9223183caf91826d9c194d7fb128fa"}], "title": "linkwatch: use __dev_put() in callers to prevent UAF", "x_generator": {"engine": "bippy-1.2.0"}}}}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nlinkwatch: use __dev_put() in callers to prevent UAF\n\nAfter linkwatch_do_dev() calls __dev_put() to release the linkwatch\nreference, the device refcount may drop to 1. At this point,\nnetdev_run_todo() can proceed (since linkwatch_sync_dev() sees an\nempty list and returns without blocking), wait for the refcount to\nbecome 1 via netdev_wait_allrefs_any(), and then free the device\nvia kobject_put().\n\nThis creates a use-after-free when __linkwatch_run_queue() tries to\ncall netdev_unlock_ops() on the already-freed device.\n\nNote that adding netdev_lock_ops()/netdev_unlock_ops() pair in\nnetdev_run_todo() before kobject_put() would not work, because\nnetdev_lock_ops() is conditional - it only locks when\nnetdev_need_ops_lock() returns true. If the device doesn't require\nops_lock, linkwatch won't hold any lock, and netdev_run_todo()\nacquiring the lock won't provide synchronization.\n\nFix this by moving __dev_put() from linkwatch_do_dev() to its\ncallers. The device reference logically pairs with de-listing the\ndevice, so it's reasonable for the caller that did the de-listing\nto release it. This allows placing __dev_put() after all device\naccesses are complete, preventing UAF.\n\nThe bug can be reproduced by adding mdelay(2000) after\nlinkwatch_do_dev() in __linkwatch_run_queue(), then running:\n\n ip tuntap add mode tun name tun_test\n ip link set tun_test up\n ip link set tun_test carrier off\n ip link set tun_test carrier on\n sleep 0.5\n ip tuntap del mode tun name tun_test\n\nKASAN report:\n\n ==================================================================\n BUG: KASAN: use-after-free in netdev_need_ops_lock include/net/netdev_lock.h:33 [inline]\n BUG: KASAN: use-after-free in netdev_unlock_ops include/net/netdev_lock.h:47 [inline]\n BUG: KASAN: use-after-free in __linkwatch_run_queue+0x865/0x8a0 net/core/link_watch.c:245\n Read of size 8 at addr ffff88804de5c008 by task kworker/u32:10/8123\n\n CPU: 0 UID: 0 PID: 8123 Comm: kworker/u32:10 Not tainted syzkaller #0 PREEMPT(full)\n Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\n Workqueue: events_unbound linkwatch_event\n Call Trace:\n <TASK>\n __dump_stack lib/dump_stack.c:94 [inline]\n dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120\n print_address_description mm/kasan/report.c:378 [inline]\n print_report+0x156/0x4c9 mm/kasan/report.c:482\n kasan_report+0xdf/0x1a0 mm/kasan/report.c:595\n netdev_need_ops_lock include/net/netdev_lock.h:33 [inline]\n netdev_unlock_ops include/net/netdev_lock.h:47 [inline]\n __linkwatch_run_queue+0x865/0x8a0 net/core/link_watch.c:245\n linkwatch_event+0x8f/0xc0 net/core/link_watch.c:304\n process_one_work+0x9c2/0x1840 kernel/workqueue.c:3257\n process_scheduled_works kernel/workqueue.c:3340 [inline]\n worker_thread+0x5da/0xe40 kernel/workqueue.c:3421\n kthread+0x3b3/0x730 kernel/kthread.c:463\n ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158\n ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246\n </TASK>\n =================================================================="}], "id": "CVE-2026-23192", "lastModified": "2026-02-14T17:15:57.020", "metrics": {}, "published": "2026-02-14T17:15:57.020", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/2718ae6af7445ba2ee0abf6365ca43a9a3b16aeb"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/83b67cc9be9223183caf91826d9c194d7fb128fa"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

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