{"api_version":"1","generated_at":"2026-08-15T18:28:29+00:00","cve":"CVE-2026-74264","urls":{"html":"https://cve.report/CVE-2026-74264","api":"https://cve.report/api/cve/CVE-2026-74264.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-74264","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-74264"},"summary":{"title":"net: watchdog: fix refcount tracking races","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: watchdog: fix refcount tracking races\n\nBlamed commit converted the untracked dev_hold()/dev_put() calls\nin the watchdog code to use the tracked dev_hold_track()/dev_put_track()\n(which were later renamed/interfaced to netdev_hold() and netdev_put()).\n\nBy introducing dev->watchdog_dev_tracker to store the\nreference tracking information without adding synchronization\nbetween netdev_watchdog_up() and dev_watchdog(), it enabled the\nrace condition where this pointer could be overwritten or freed\nconcurrently, leading to the list corruption crash syzbot reported:\n\nlist_del corruption, ffff888114a18c00->next is NULL\n kernel BUG at lib/list_debug.c:52 !\nOops: invalid opcode: 0000 [#1] SMP KASAN PTI\nCPU: 1 UID: 0 PID: 91 Comm: kworker/u8:5 Not tainted syzkaller #0 PREEMPT(lazy)\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026\nWorkqueue: events_unbound linkwatch_event\n RIP: 0010:__list_del_entry_valid_or_report.cold+0x22/0x2a lib/list_debug.c:52\nCall Trace:\n <TASK>\n  __list_del_entry_valid include/linux/list.h:132 [inline]\n  __list_del_entry include/linux/list.h:246 [inline]\n  list_move_tail include/linux/list.h:341 [inline]\n  ref_tracker_free+0x1a7/0x6c0 lib/ref_tracker.c:329\n  netdev_tracker_free include/linux/netdevice.h:4491 [inline]\n  netdev_put include/linux/netdevice.h:4508 [inline]\n  netdev_put include/linux/netdevice.h:4504 [inline]\n  netdev_watchdog_down net/sched/sch_generic.c:600 [inline]\n  dev_deactivate_many+0x28c/0xfe0 net/sched/sch_generic.c:1363\n  dev_deactivate+0x109/0x1d0 net/sched/sch_generic.c:1397\n  linkwatch_do_dev net/core/link_watch.c:184 [inline]\n  linkwatch_do_dev+0xd3/0x120 net/core/link_watch.c:166\n  __linkwatch_run_queue+0x3a5/0x810 net/core/link_watch.c:240\n  linkwatch_event+0x8f/0xc0 net/core/link_watch.c:314\n  process_one_work+0xa0e/0x1980 kernel/workqueue.c:3314\n  process_scheduled_works kernel/workqueue.c:3397 [inline]\n  worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478\n  kthread+0x370/0x450 kernel/kthread.c:436\n  ret_from_fork+0x69a/0xc80 arch/x86/kernel/process.c:158\n  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245\n\nThis patch has three coordinated parts:\n\n1) Add dev->watchdog_lock and dev->watchdog_ref_held to serialize watchdog operations.\n\n2) Remove netdev_watchdog_up() call from netif_carrier_on():\n   This ensures netdev_watchdog_up() is only called from process/BH context\n   (via linkwatch workqueue dev_activate()), allowing us to use\n   spin_lock_bh() for synchronization.\n\n3) Synchronize watchdog up and watchdog timer:\n   Protect netdev_watchdog_up() with tx_global_lock and watchdog_lock.\n   Only allocate a new tracker in netdev_watchdog_up() if one is\n   not already present.\n   In dev_watchdog(), ensure we don't release the tracker if the\n   timer was rescheduled either by dev_watchdog() itself or concurrently\n   by netdev_watchdog_up().","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-15 06:22:25","updated_at":"2026-08-15 06:22:25"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/8eed5519e496b7a07f441a0f579cb228a33189f7","name":"https://git.kernel.org/stable/c/8eed5519e496b7a07f441a0f579cb228a33189f7","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/7ce2b00ff058ec4cafc9b447e1f0a6d6f49275d9","name":"https://git.kernel.org/stable/c/7ce2b00ff058ec4cafc9b447e1f0a6d6f49275d9","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/446fe8ce699ce0a4d702f7b0fcdb50de340b9260","name":"https://git.kernel.org/stable/c/446fe8ce699ce0a4d702f7b0fcdb50de340b9260","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-74264","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74264","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected f12bf6f3f942b37de65eeea8be25903587fec930 446fe8ce699ce0a4d702f7b0fcdb50de340b9260 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected f12bf6f3f942b37de65eeea8be25903587fec930 7ce2b00ff058ec4cafc9b447e1f0a6d6f49275d9 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected f12bf6f3f942b37de65eeea8be25903587fec930 8eed5519e496b7a07f441a0f579cb228a33189f7 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.17","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.17 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.40 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.5 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["include/linux/netdevice.h","net/core/dev.c","net/sched/sch_generic.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"446fe8ce699ce0a4d702f7b0fcdb50de340b9260","status":"affected","version":"f12bf6f3f942b37de65eeea8be25903587fec930","versionType":"git"},{"lessThan":"7ce2b00ff058ec4cafc9b447e1f0a6d6f49275d9","status":"affected","version":"f12bf6f3f942b37de65eeea8be25903587fec930","versionType":"git"},{"lessThan":"8eed5519e496b7a07f441a0f579cb228a33189f7","status":"affected","version":"f12bf6f3f942b37de65eeea8be25903587fec930","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["include/linux/netdevice.h","net/core/dev.c","net/sched/sch_generic.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.17"},{"lessThan":"5.17","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.40","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.5","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.40","versionStartIncluding":"5.17","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.5","versionStartIncluding":"5.17","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2-rc1","versionStartIncluding":"5.17","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: watchdog: fix refcount tracking races\n\nBlamed commit converted the untracked dev_hold()/dev_put() calls\nin the watchdog code to use the tracked dev_hold_track()/dev_put_track()\n(which were later renamed/interfaced to netdev_hold() and netdev_put()).\n\nBy introducing dev->watchdog_dev_tracker to store the\nreference tracking information without adding synchronization\nbetween netdev_watchdog_up() and dev_watchdog(), it enabled the\nrace condition where this pointer could be overwritten or freed\nconcurrently, leading to the list corruption crash syzbot reported:\n\nlist_del corruption, ffff888114a18c00->next is NULL\n kernel BUG at lib/list_debug.c:52 !\nOops: invalid opcode: 0000 [#1] SMP KASAN PTI\nCPU: 1 UID: 0 PID: 91 Comm: kworker/u8:5 Not tainted syzkaller #0 PREEMPT(lazy)\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026\nWorkqueue: events_unbound linkwatch_event\n RIP: 0010:__list_del_entry_valid_or_report.cold+0x22/0x2a lib/list_debug.c:52\nCall Trace:\n <TASK>\n  __list_del_entry_valid include/linux/list.h:132 [inline]\n  __list_del_entry include/linux/list.h:246 [inline]\n  list_move_tail include/linux/list.h:341 [inline]\n  ref_tracker_free+0x1a7/0x6c0 lib/ref_tracker.c:329\n  netdev_tracker_free include/linux/netdevice.h:4491 [inline]\n  netdev_put include/linux/netdevice.h:4508 [inline]\n  netdev_put include/linux/netdevice.h:4504 [inline]\n  netdev_watchdog_down net/sched/sch_generic.c:600 [inline]\n  dev_deactivate_many+0x28c/0xfe0 net/sched/sch_generic.c:1363\n  dev_deactivate+0x109/0x1d0 net/sched/sch_generic.c:1397\n  linkwatch_do_dev net/core/link_watch.c:184 [inline]\n  linkwatch_do_dev+0xd3/0x120 net/core/link_watch.c:166\n  __linkwatch_run_queue+0x3a5/0x810 net/core/link_watch.c:240\n  linkwatch_event+0x8f/0xc0 net/core/link_watch.c:314\n  process_one_work+0xa0e/0x1980 kernel/workqueue.c:3314\n  process_scheduled_works kernel/workqueue.c:3397 [inline]\n  worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478\n  kthread+0x370/0x450 kernel/kthread.c:436\n  ret_from_fork+0x69a/0xc80 arch/x86/kernel/process.c:158\n  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245\n\nThis patch has three coordinated parts:\n\n1) Add dev->watchdog_lock and dev->watchdog_ref_held to serialize watchdog operations.\n\n2) Remove netdev_watchdog_up() call from netif_carrier_on():\n   This ensures netdev_watchdog_up() is only called from process/BH context\n   (via linkwatch workqueue dev_activate()), allowing us to use\n   spin_lock_bh() for synchronization.\n\n3) Synchronize watchdog up and watchdog timer:\n   Protect netdev_watchdog_up() with tx_global_lock and watchdog_lock.\n   Only allocate a new tracker in netdev_watchdog_up() if one is\n   not already present.\n   In dev_watchdog(), ensure we don't release the tracker if the\n   timer was rescheduled either by dev_watchdog() itself or concurrently\n   by netdev_watchdog_up()."}],"providerMetadata":{"dateUpdated":"2026-08-15T05:57:40.314Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/446fe8ce699ce0a4d702f7b0fcdb50de340b9260"},{"url":"https://git.kernel.org/stable/c/7ce2b00ff058ec4cafc9b447e1f0a6d6f49275d9"},{"url":"https://git.kernel.org/stable/c/8eed5519e496b7a07f441a0f579cb228a33189f7"}],"title":"net: watchdog: fix refcount tracking races","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-74264","datePublished":"2026-08-15T05:57:40.314Z","dateReserved":"2026-08-15T05:44:03.877Z","dateUpdated":"2026-08-15T05:57:40.314Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-15 06:22:25","lastModifiedDate":"2026-08-15 06:22:25","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"74264","Ordinal":"1","Title":"net: watchdog: fix refcount tracking races","CVE":"CVE-2026-74264","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"74264","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: watchdog: fix refcount tracking races\n\nBlamed commit converted the untracked dev_hold()/dev_put() calls\nin the watchdog code to use the tracked dev_hold_track()/dev_put_track()\n(which were later renamed/interfaced to netdev_hold() and netdev_put()).\n\nBy introducing dev->watchdog_dev_tracker to store the\nreference tracking information without adding synchronization\nbetween netdev_watchdog_up() and dev_watchdog(), it enabled the\nrace condition where this pointer could be overwritten or freed\nconcurrently, leading to the list corruption crash syzbot reported:\n\nlist_del corruption, ffff888114a18c00->next is NULL\n kernel BUG at lib/list_debug.c:52 !\nOops: invalid opcode: 0000 [#1] SMP KASAN PTI\nCPU: 1 UID: 0 PID: 91 Comm: kworker/u8:5 Not tainted syzkaller #0 PREEMPT(lazy)\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026\nWorkqueue: events_unbound linkwatch_event\n RIP: 0010:__list_del_entry_valid_or_report.cold+0x22/0x2a lib/list_debug.c:52\nCall Trace:\n <TASK>\n  __list_del_entry_valid include/linux/list.h:132 [inline]\n  __list_del_entry include/linux/list.h:246 [inline]\n  list_move_tail include/linux/list.h:341 [inline]\n  ref_tracker_free+0x1a7/0x6c0 lib/ref_tracker.c:329\n  netdev_tracker_free include/linux/netdevice.h:4491 [inline]\n  netdev_put include/linux/netdevice.h:4508 [inline]\n  netdev_put include/linux/netdevice.h:4504 [inline]\n  netdev_watchdog_down net/sched/sch_generic.c:600 [inline]\n  dev_deactivate_many+0x28c/0xfe0 net/sched/sch_generic.c:1363\n  dev_deactivate+0x109/0x1d0 net/sched/sch_generic.c:1397\n  linkwatch_do_dev net/core/link_watch.c:184 [inline]\n  linkwatch_do_dev+0xd3/0x120 net/core/link_watch.c:166\n  __linkwatch_run_queue+0x3a5/0x810 net/core/link_watch.c:240\n  linkwatch_event+0x8f/0xc0 net/core/link_watch.c:314\n  process_one_work+0xa0e/0x1980 kernel/workqueue.c:3314\n  process_scheduled_works kernel/workqueue.c:3397 [inline]\n  worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478\n  kthread+0x370/0x450 kernel/kthread.c:436\n  ret_from_fork+0x69a/0xc80 arch/x86/kernel/process.c:158\n  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245\n\nThis patch has three coordinated parts:\n\n1) Add dev->watchdog_lock and dev->watchdog_ref_held to serialize watchdog operations.\n\n2) Remove netdev_watchdog_up() call from netif_carrier_on():\n   This ensures netdev_watchdog_up() is only called from process/BH context\n   (via linkwatch workqueue dev_activate()), allowing us to use\n   spin_lock_bh() for synchronization.\n\n3) Synchronize watchdog up and watchdog timer:\n   Protect netdev_watchdog_up() with tx_global_lock and watchdog_lock.\n   Only allocate a new tracker in netdev_watchdog_up() if one is\n   not already present.\n   In dev_watchdog(), ensure we don't release the tracker if the\n   timer was rescheduled either by dev_watchdog() itself or concurrently\n   by netdev_watchdog_up().","Type":"Description","Title":"net: watchdog: fix refcount tracking races"}]}}}