{"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":"2026-05-11T22:02:06.374Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-05-11T22:02:06.374Z"},"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 =================================================================="}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"}}],"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"}}}}