GHSA-52XP-VQWJ-RP88

Vulnerability from github – Published: 2026-10-23 12:31 – Updated: 2026-10-23 12:31
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

net: bridge: remove stale rcu_barrier() in br_multicast_dev_del()

This rcu_barrier() came from a time call_rcu() calls were used in net/bridge/br_multicast.c.

Now kfree_rcu() is there, we can remove this problematic rcu_barrier() which causes extreme RTNL pressure in many syzbot reports.

INFO: task syz-executor:77945 is blocked on a mutex likely owned by task kworker/u1024:5:36537. task:kworker/u1024:5 state:D stack:24616 pid:36537 tgid:36537 ppid:2 task_flags:0x4208060 flags:0x00080000 last_sleep:612797637337 Workqueue: netns cleanup_net Call Trace: [] context_switch+0xf2a/0x1730 kernel/sched/core.c:6483 [] __schedule+0x1133/0x43a0 kernel/sched/core.c:8411 [] __schedule_loop kernel/sched/core.c:8514 [inline] [] schedule+0xab/0x260 kernel/sched/core.c:8529 [] schedule_timeout+0xc3/0x2b0 kernel/time/sleep_timeout.c:75 [] do_wait_for_common kernel/sched/completion.c:100 [inline] [] __wait_for_common kernel/sched/completion.c:121 [inline] [] wait_for_common kernel/sched/completion.c:132 [inline] [] wait_for_completion+0x2c7/0x5d0 kernel/sched/completion.c:153 [] rcu_barrier+0x49f/0x620 kernel/rcu/tree.c:3888 [] br_multicast_dev_del+0x303/0x350 net/bridge/br_multicast.c:4459 [] br_dev_uninit+0x1c/0x40 net/bridge/br_device.c:157 [] unregister_netdevice_many_notify+0x1c1c/0x2300 net/core/dev.c:12599 [] ops_exit_rtnl_list net/core/net_namespace.c:187 [inline] [] ops_undo_list+0x3d3/0x940 net/core/net_namespace.c:248

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{
  "affected": [],
  "aliases": [
    "CVE-2026-98881"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-23T12:18:21Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: bridge: remove stale rcu_barrier() in br_multicast_dev_del()\n\nThis rcu_barrier() came from a time call_rcu() calls were used in\nnet/bridge/br_multicast.c.\n\nNow kfree_rcu() is there, we can remove this problematic rcu_barrier()\nwhich causes extreme RTNL pressure in many syzbot reports.\n\nINFO: task syz-executor:77945 is blocked on a mutex likely owned by task kworker/u1024:5:36537.\ntask:kworker/u1024:5 state:D stack:24616 pid:36537 tgid:36537 ppid:2      task_flags:0x4208060 flags:0x00080000 last_sleep:612797637337\nWorkqueue: netns cleanup_net\nCall Trace:\n \u003cTASK\u003e\n  [\u003cffffffff81914eaa\u003e] context_switch+0xf2a/0x1730 kernel/sched/core.c:6483\n  [\u003cffffffff81201143\u003e] __schedule+0x1133/0x43a0 kernel/sched/core.c:8411\n  [\u003cffffffff8120446b\u003e] __schedule_loop kernel/sched/core.c:8514 [inline]\n  [\u003cffffffff8120446b\u003e] schedule+0xab/0x260 kernel/sched/core.c:8529\n  [\u003cffffffff8121a093\u003e] schedule_timeout+0xc3/0x2b0 kernel/time/sleep_timeout.c:75\n  [\u003cffffffff81205347\u003e] do_wait_for_common kernel/sched/completion.c:100 [inline]\n  [\u003cffffffff81205347\u003e] __wait_for_common kernel/sched/completion.c:121 [inline]\n  [\u003cffffffff81205347\u003e] wait_for_common kernel/sched/completion.c:132 [inline]\n  [\u003cffffffff81205347\u003e] wait_for_completion+0x2c7/0x5d0 kernel/sched/completion.c:153\n  [\u003cffffffff81b8f27f\u003e] rcu_barrier+0x49f/0x620 kernel/rcu/tree.c:3888\n  [\u003cffffffff860091b3\u003e] br_multicast_dev_del+0x303/0x350 net/bridge/br_multicast.c:4459\n  [\u003cffffffff85fb5dbc\u003e] br_dev_uninit+0x1c/0x40 net/bridge/br_device.c:157\n  [\u003cffffffff8568058c\u003e] unregister_netdevice_many_notify+0x1c1c/0x2300 net/core/dev.c:12599\n  [\u003cffffffff8562be43\u003e] ops_exit_rtnl_list net/core/net_namespace.c:187 [inline]\n  [\u003cffffffff8562be43\u003e] ops_undo_list+0x3d3/0x940 net/core/net_namespace.c:248",
  "id": "GHSA-52xp-vqwj-rp88",
  "modified": "2026-10-23T12:31:36Z",
  "published": "2026-10-23T12:31:36Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98881"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0443f6aac6bf6a91e406273fdda11497cef6ad07"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/25ae123db10ba9ab890b56bcdb0a4363aee8529a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/35f9f11740515a10b084adfb1ce691351f2452ab"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/372ee8fbe0f796031c60f676ec90f0788c26523d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/39679927fa7aaf4601119f7234342d1b5d4f6f84"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ac0e823a228f94ad9d7a3d876cc07e59a7afb806"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f0018acf0b66f93a292667c9a9c2a26c570cf270"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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