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

{
  "id": "d743dfd6b63f91176a2a61acadb3119c90cda6bce5d07eedde7b11aed1f34d42",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-98881",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "net: bridge: remove stale rcu_barrier() in br_multicast_dev_del()",
    "summary": "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",
    "evidence": "cve:CVE-2026-98881",
    "products": [
      {
        "name": {
          "value": "Linux",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      },
      {
        "name": {
          "value": "Linux",
          "evidence": "/containers/cna/affected/1/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-98881",
      "aliases": [
        "CVE-2026-98881"
      ],
      "metrics": [],
      "affected": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "19e3a9c90c53479fecaa02307bf2db5ab8b3ffe3",
              "lessThan": "35f9f11740515a10b084adfb1ce691351f2452ab",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "19e3a9c90c53479fecaa02307bf2db5ab8b3ffe3",
              "lessThan": "0443f6aac6bf6a91e406273fdda11497cef6ad07",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "19e3a9c90c53479fecaa02307bf2db5ab8b3ffe3",
              "lessThan": "ac0e823a228f94ad9d7a3d876cc07e59a7afb806",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "19e3a9c90c53479fecaa02307bf2db5ab8b3ffe3",
              "lessThan": "f0018acf0b66f93a292667c9a9c2a26c570cf270",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "19e3a9c90c53479fecaa02307bf2db5ab8b3ffe3",
              "lessThan": "372ee8fbe0f796031c60f676ec90f0788c26523d",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "19e3a9c90c53479fecaa02307bf2db5ab8b3ffe3",
              "lessThan": "39679927fa7aaf4601119f7234342d1b5d4f6f84",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "19e3a9c90c53479fecaa02307bf2db5ab8b3ffe3",
              "lessThan": "25ae123db10ba9ab890b56bcdb0a4363aee8529a",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "net/bridge/br_multicast.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.0"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.10.271",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.15.222",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.189",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.158",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "net/bridge/br_multicast.c"
          ],
          "defaultStatus": "affected"
        }
      ],
      "modified": "2026-10-26T06:56:04.487Z",
      "provider": "cve",
      "references": [
        "https://git.kernel.org/stable/c/35f9f11740515a10b084adfb1ce691351f2452ab",
        "https://git.kernel.org/stable/c/0443f6aac6bf6a91e406273fdda11497cef6ad07",
        "https://git.kernel.org/stable/c/ac0e823a228f94ad9d7a3d876cc07e59a7afb806",
        "https://git.kernel.org/stable/c/f0018acf0b66f93a292667c9a9c2a26c570cf270",
        "https://git.kernel.org/stable/c/372ee8fbe0f796031c60f676ec90f0788c26523d",
        "https://git.kernel.org/stable/c/39679927fa7aaf4601119f7234342d1b5d4f6f84",
        "https://git.kernel.org/stable/c/25ae123db10ba9ab890b56bcdb0a4363aee8529a"
      ],
      "provider_metadata": {
        "cna": {
          "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
          "shortName": "Linux",
          "dateUpdated": "2026-10-26T06:56:04.487Z"
        }
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-98881",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-cve",
  "document_id": 263339,
  "published_at": "2026-10-23T11:37:32.327+00:00"
}