FKIE_CVE-2026-74264

Vulnerability from fkie_nvd - Published: 2026-08-15 06:22 - Updated: 2026-10-30 13:19
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: net: watchdog: fix refcount tracking races Blamed commit converted the untracked dev_hold()/dev_put() calls in the watchdog code to use the tracked dev_hold_track()/dev_put_track() (which were later renamed/interfaced to netdev_hold() and netdev_put()). By introducing dev->watchdog_dev_tracker to store the reference tracking information without adding synchronization between netdev_watchdog_up() and dev_watchdog(), it enabled the race condition where this pointer could be overwritten or freed concurrently, leading to the list corruption crash syzbot reported: list_del corruption, ffff888114a18c00->next is NULL kernel BUG at lib/list_debug.c:52 ! Oops: invalid opcode: 0000 [#1] SMP KASAN PTI CPU: 1 UID: 0 PID: 91 Comm: kworker/u8:5 Not tainted syzkaller #0 PREEMPT(lazy) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: events_unbound linkwatch_event RIP: 0010:__list_del_entry_valid_or_report.cold+0x22/0x2a lib/list_debug.c:52 Call Trace: <TASK> __list_del_entry_valid include/linux/list.h:132 [inline] __list_del_entry include/linux/list.h:246 [inline] list_move_tail include/linux/list.h:341 [inline] ref_tracker_free+0x1a7/0x6c0 lib/ref_tracker.c:329 netdev_tracker_free include/linux/netdevice.h:4491 [inline] netdev_put include/linux/netdevice.h:4508 [inline] netdev_put include/linux/netdevice.h:4504 [inline] netdev_watchdog_down net/sched/sch_generic.c:600 [inline] dev_deactivate_many+0x28c/0xfe0 net/sched/sch_generic.c:1363 dev_deactivate+0x109/0x1d0 net/sched/sch_generic.c:1397 linkwatch_do_dev net/core/link_watch.c:184 [inline] linkwatch_do_dev+0xd3/0x120 net/core/link_watch.c:166 __linkwatch_run_queue+0x3a5/0x810 net/core/link_watch.c:240 linkwatch_event+0x8f/0xc0 net/core/link_watch.c:314 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3314 process_scheduled_works kernel/workqueue.c:3397 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x69a/0xc80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 This patch has three coordinated parts: 1) Add dev->watchdog_lock and dev->watchdog_ref_held to serialize watchdog operations. 2) Remove netdev_watchdog_up() call from netif_carrier_on(): This ensures netdev_watchdog_up() is only called from process/BH context (via linkwatch workqueue dev_activate()), allowing us to use spin_lock_bh() for synchronization. 3) Synchronize watchdog up and watchdog timer: Protect netdev_watchdog_up() with tx_global_lock and watchdog_lock. Only allocate a new tracker in netdev_watchdog_up() if one is not already present. In dev_watchdog(), ensure we don't release the tracker if the timer was rescheduled either by dev_watchdog() itself or concurrently by netdev_watchdog_up().
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2fc2c92320272a99e18bbb102252859b6ee50881
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/446fe8ce699ce0a4d702f7b0fcdb50de340b9260
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6b2330facc90e43b6d7171a0ac12c23dfcbdc30d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7ce2b00ff058ec4cafc9b447e1f0a6d6f49275d9
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8eed5519e496b7a07f441a0f579cb228a33189f7
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/fbb8e79c117adcbfafef33b81d0db853b461bdac
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "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": "fbb8e79c117adcbfafef33b81d0db853b461bdac",
              "status": "affected",
              "version": "f12bf6f3f942b37de65eeea8be25903587fec930",
              "versionType": "git"
            },
            {
              "lessThan": "2fc2c92320272a99e18bbb102252859b6ee50881",
              "status": "affected",
              "version": "f12bf6f3f942b37de65eeea8be25903587fec930",
              "versionType": "git"
            },
            {
              "lessThan": "6b2330facc90e43b6d7171a0ac12c23dfcbdc30d",
              "status": "affected",
              "version": "f12bf6f3f942b37de65eeea8be25903587fec930",
              "versionType": "git"
            },
            {
              "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": "6.1.*",
              "status": "unaffected",
              "version": "6.1.191",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.160",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.114",
              "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",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "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-\u003ewatchdog_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-\u003enext 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 \u003cTASK\u003e\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-\u003ewatchdog_lock and dev-\u003ewatchdog_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\u0027t release the tracker if the\n   timer was rescheduled either by dev_watchdog() itself or concurrently\n   by netdev_watchdog_up()."
    }
  ],
  "id": "CVE-2026-74264",
  "lastModified": "2026-10-30T13:19:53.890",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-74264",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-10-16T18:51:40.430593Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-15T06:22:25.670",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2fc2c92320272a99e18bbb102252859b6ee50881"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/446fe8ce699ce0a4d702f7b0fcdb50de340b9260"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6b2330facc90e43b6d7171a0ac12c23dfcbdc30d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7ce2b00ff058ec4cafc9b447e1f0a6d6f49275d9"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8eed5519e496b7a07f441a0f579cb228a33189f7"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/fbb8e79c117adcbfafef33b81d0db853b461bdac"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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