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CVE-2026-98881

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

Linux LinuxOperating systems
Open in ThreatlineRecord JSON
CVSS
NoneNot scored
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)No scoreNo FIRST EPSS score in this snapshot yet
Fixed in35f9f11740515a10b084adfb1ce691351f2452abAlso 0443f6aac6bf6a91e406273fdda11497cef6ad07, 372ee8fbe0f796031c60f676ec90f0788c26523d and 8 moreCVE List
Published23 Oct 2026Updated 23 Oct 2026CVE List

What fixes it

  • 35f9f11740515a10b084adfb1ce691351f2452abLinuxCVE List
  • 0443f6aac6bf6a91e406273fdda11497cef6ad07LinuxCVE List
  • 372ee8fbe0f796031c60f676ec90f0788c26523dLinuxCVE List
  • 39679927fa7aaf4601119f7234342d1b5d4f6f84LinuxCVE List
  • 25ae123db10ba9ab890b56bcdb0a4363aee8529aLinuxCVE List
  • 5.10.271LinuxCVE List
Show all 11 fixed versions

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Description

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: <TASK> [<ffffffff81914eaa>] context_switch+0xf2a/0x1730 kernel/sched/core.c:6483 [<ffffffff81201143>] __schedule+0x1133/0x43a0 kernel/sched/core.c:8411 [<ffffffff8120446b>] __schedule_loop kernel/sched/core.c:8514 [inline] [<ffffffff8120446b>] schedule+0xab/0x260 kernel/sched/core.c:8529 [<ffffffff8121a093>] schedule_timeout+0xc3/0x2b0 kernel/time/sleep_timeout.c:75 [<ffffffff81205347>] do_wait_for_common kernel/sched/completion.c:100 [inline] [<ffffffff81205347>] __wait_for_common kernel/sched/completion.c:121 [inline] [<ffffffff81205347>] wait_for_common kernel/sched/completion.c:132 [inline] [<ffffffff81205347>] wait_for_completion+0x2c7/0x5d0 kernel/sched/completion.c:153 [<ffffffff81b8f27f>] rcu_barrier+0x49f/0x620 kernel/rcu/tree.c:3888 [<ffffffff860091b3>] br_multicast_dev_del+0x303/0x350 net/bridge/br_multicast.c:4459 [<ffffffff85fb5dbc>] br_dev_uninit+0x1c/0x40 net/bridge/br_device.c:157 [<ffffffff8568058c>] unregister_netdevice_many_notify+0x1c1c/0x2300 net/core/dev.c:12599 [<ffffffff8562be43>] ops_exit_rtnl_list net/core/net_namespace.c:187 [inline] [<ffffffff8562be43>] ops_undo_list+0x3d3/0x940 net/core/net_namespace.c:248

Text from CVE List

Affected versions 20

  • Linuxaffected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 35f9f11740515a10b084adfb1ce691351f2452abCVE List
  • Linuxaffected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 0443f6aac6bf6a91e406273fdda11497cef6ad07CVE List
  • Linuxaffected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before ac0e823a228f94ad9d7a3d876cc07e59a7afb806CVE List
  • Linuxaffected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before f0018acf0b66f93a292667c9a9c2a26c570cf270CVE List
  • Linuxaffected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 372ee8fbe0f796031c60f676ec90f0788c26523dCVE List
  • Linuxaffected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 39679927fa7aaf4601119f7234342d1b5d4f6f84CVE List
  • Linuxaffected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 25ae123db10ba9ab890b56bcdb0a4363aee8529aCVE List
  • Linuxaffected: all versions before 5.10.271CVE List
  • Linuxaffected: all versions before 5.15.222CVE List
  • Linuxaffected: all versions before 6.1.189CVE List
  • Linuxaffected: all versions before 6.6.158CVE List
  • Linuxaffected: all versions before 6.12.111CVE List
  • Linuxaffected: all versions before 6.18.53CVE List
  • Linuxunaffected: 5.10.271 through 5.10.*CVE List
  • Linuxunaffected: 5.15.222 through 5.15.*CVE List
  • Linuxunaffected: 6.1.189 through 6.1.*CVE List
  • Linuxunaffected: 6.6.158 through 6.6.*CVE List
  • Linuxunaffected: 6.12.111 through 6.12.*CVE List
  • Linuxunaffected: 6.18.53 through 6.18.*CVE List
  • Linuxunaffected: 7.2CVE List

References 7