Vulnerability-Lookup

CVE-2026-43100 (GCVE-0-2026-43100)

Vulnerability from cvelistv5 – Published: 2026-05-06 07:40 – Updated: 2026-05-06 07:40

Title

bridge: guard local VLAN-0 FDB helpers against NULL vlan group

Summary

In the Linux kernel, the following vulnerability has been resolved: bridge: guard local VLAN-0 FDB helpers against NULL vlan group When CONFIG_BRIDGE_VLAN_FILTERING is not set, br_vlan_group() and nbp_vlan_group() return NULL (br_private.h stub definitions). The BR_BOOLOPT_FDB_LOCAL_VLAN_0 toggle code is compiled unconditionally and reaches br_fdb_delete_locals_per_vlan_port() and br_fdb_insert_locals_per_vlan_port(), where the NULL vlan group pointer is dereferenced via list_for_each_entry(v, &vg->vlan_list, vlist). The observed crash is in the delete path, triggered when creating a bridge with IFLA_BR_MULTI_BOOLOPT containing BR_BOOLOPT_FDB_LOCAL_VLAN_0 via RTM_NEWLINK. The insert helper has the same bug pattern. Oops: general protection fault, probably for non-canonical address 0xdffffc0000000056: 0000 [#1] KASAN NOPTI KASAN: null-ptr-deref in range [0x00000000000002b0-0x00000000000002b7] RIP: 0010:br_fdb_delete_locals_per_vlan+0x2b9/0x310 Call Trace: br_fdb_toggle_local_vlan_0+0x452/0x4c0 br_toggle_fdb_local_vlan_0+0x31/0x80 net/bridge/br.c:276 br_boolopt_toggle net/bridge/br.c:313 br_boolopt_multi_toggle net/bridge/br.c:364 br_changelink net/bridge/br_netlink.c:1542 br_dev_newlink net/bridge/br_netlink.c:1575 Add NULL checks for the vlan group pointer in both helpers, returning early when there are no VLANs to iterate. This matches the existing pattern used by other bridge FDB functions such as br_fdb_add() and br_fdb_delete().

Severity ?

No CVSS data available.

Assigner

Linux

References

URL

Tags

	https://git.kernel.org/stable/c/fb612d436ff031765…
	https://git.kernel.org/stable/c/ddf0ec2d600e7dad6…
	https://git.kernel.org/stable/c/1979645e1842cb701…

Impacted products

Vendor

Product

Version

Linux

Affected: 21446c06b441b9c993870efae71aef4e9aa72ec7 , < fb612d436ff0317659e45a91c25fd7d9516f5b1b (git)
Affected: 21446c06b441b9c993870efae71aef4e9aa72ec7 , < ddf0ec2d600e7dad62b89692749534d7900a732a (git)
Affected: 21446c06b441b9c993870efae71aef4e9aa72ec7 , < 1979645e1842cb7017525a61a0e0e0beb924d02a (git)

Linux

Affected: 6.18
Unaffected: 0 , < 6.18 (semver)
Unaffected: 6.18.24 , ≤ 6.18.* (semver)
Unaffected: 6.19.14 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/bridge/br_fdb.c"
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          "vendor": "Linux",
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              "versionType": "git"
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            {
              "lessThan": "ddf0ec2d600e7dad62b89692749534d7900a732a",
              "status": "affected",
              "version": "21446c06b441b9c993870efae71aef4e9aa72ec7",
              "versionType": "git"
            },
            {
              "lessThan": "1979645e1842cb7017525a61a0e0e0beb924d02a",
              "status": "affected",
              "version": "21446c06b441b9c993870efae71aef4e9aa72ec7",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/bridge/br_fdb.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.18"
            },
            {
              "lessThan": "6.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.24",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.14",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.24",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.14",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbridge: guard local VLAN-0 FDB helpers against NULL vlan group\n\nWhen CONFIG_BRIDGE_VLAN_FILTERING is not set, br_vlan_group() and\nnbp_vlan_group() return NULL (br_private.h stub definitions). The\nBR_BOOLOPT_FDB_LOCAL_VLAN_0 toggle code is compiled unconditionally and\nreaches br_fdb_delete_locals_per_vlan_port() and\nbr_fdb_insert_locals_per_vlan_port(), where the NULL vlan group pointer\nis dereferenced via list_for_each_entry(v, \u0026vg-\u003evlan_list, vlist).\n\nThe observed crash is in the delete path, triggered when creating a\nbridge with IFLA_BR_MULTI_BOOLOPT containing BR_BOOLOPT_FDB_LOCAL_VLAN_0\nvia RTM_NEWLINK. The insert helper has the same bug pattern.\n\n  Oops: general protection fault, probably for non-canonical address 0xdffffc0000000056: 0000 [#1] KASAN NOPTI\n  KASAN: null-ptr-deref in range [0x00000000000002b0-0x00000000000002b7]\n  RIP: 0010:br_fdb_delete_locals_per_vlan+0x2b9/0x310\n  Call Trace:\n   br_fdb_toggle_local_vlan_0+0x452/0x4c0\n   br_toggle_fdb_local_vlan_0+0x31/0x80 net/bridge/br.c:276\n   br_boolopt_toggle net/bridge/br.c:313\n   br_boolopt_multi_toggle net/bridge/br.c:364\n   br_changelink net/bridge/br_netlink.c:1542\n   br_dev_newlink net/bridge/br_netlink.c:1575\n\nAdd NULL checks for the vlan group pointer in both helpers, returning\nearly when there are no VLANs to iterate. This matches the existing\npattern used by other bridge FDB functions such as br_fdb_add() and\nbr_fdb_delete()."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-06T07:40:30.309Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/fb612d436ff0317659e45a91c25fd7d9516f5b1b"
        },
        {
          "url": "https://git.kernel.org/stable/c/ddf0ec2d600e7dad62b89692749534d7900a732a"
        },
        {
          "url": "https://git.kernel.org/stable/c/1979645e1842cb7017525a61a0e0e0beb924d02a"
        }
      ],
      "title": "bridge: guard local VLAN-0 FDB helpers against NULL vlan group",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43100",
    "datePublished": "2026-05-06T07:40:30.309Z",
    "dateReserved": "2026-05-01T14:12:55.984Z",
    "dateUpdated": "2026-05-06T07:40:30.309Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-43100",
      "date": "2026-05-08",
      "epss": "0.00017",
      "percentile": "0.04094"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-43100\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-05-06T10:16:23.523\",\"lastModified\":\"2026-05-06T13:07:51.607\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nbridge: guard local VLAN-0 FDB helpers against NULL vlan group\\n\\nWhen CONFIG_BRIDGE_VLAN_FILTERING is not set, br_vlan_group() and\\nnbp_vlan_group() return NULL (br_private.h stub definitions). The\\nBR_BOOLOPT_FDB_LOCAL_VLAN_0 toggle code is compiled unconditionally and\\nreaches br_fdb_delete_locals_per_vlan_port() and\\nbr_fdb_insert_locals_per_vlan_port(), where the NULL vlan group pointer\\nis dereferenced via list_for_each_entry(v, \u0026vg-\u003evlan_list, vlist).\\n\\nThe observed crash is in the delete path, triggered when creating a\\nbridge with IFLA_BR_MULTI_BOOLOPT containing BR_BOOLOPT_FDB_LOCAL_VLAN_0\\nvia RTM_NEWLINK. The insert helper has the same bug pattern.\\n\\n  Oops: general protection fault, probably for non-canonical address 0xdffffc0000000056: 0000 [#1] KASAN NOPTI\\n  KASAN: null-ptr-deref in range [0x00000000000002b0-0x00000000000002b7]\\n  RIP: 0010:br_fdb_delete_locals_per_vlan+0x2b9/0x310\\n  Call Trace:\\n   br_fdb_toggle_local_vlan_0+0x452/0x4c0\\n   br_toggle_fdb_local_vlan_0+0x31/0x80 net/bridge/br.c:276\\n   br_boolopt_toggle net/bridge/br.c:313\\n   br_boolopt_multi_toggle net/bridge/br.c:364\\n   br_changelink net/bridge/br_netlink.c:1542\\n   br_dev_newlink net/bridge/br_netlink.c:1575\\n\\nAdd NULL checks for the vlan group pointer in both helpers, returning\\nearly when there are no VLANs to iterate. This matches the existing\\npattern used by other bridge FDB functions such as br_fdb_add() and\\nbr_fdb_delete().\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/1979645e1842cb7017525a61a0e0e0beb924d02a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ddf0ec2d600e7dad62b89692749534d7900a732a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/fb612d436ff0317659e45a91c25fd7d9516f5b1b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}

FKIE_CVE-2026-43100

Vulnerability from fkie_nvd - Published: 2026-05-06 10:16 - Updated: 2026-05-06 13:07

Severity ?

Summary

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/1979645e1842cb7017525a61a0e0e0beb924d02a
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/ddf0ec2d600e7dad62b89692749534d7900a732a
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/fb612d436ff0317659e45a91c25fd7d9516f5b1b

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbridge: guard local VLAN-0 FDB helpers against NULL vlan group\n\nWhen CONFIG_BRIDGE_VLAN_FILTERING is not set, br_vlan_group() and\nnbp_vlan_group() return NULL (br_private.h stub definitions). The\nBR_BOOLOPT_FDB_LOCAL_VLAN_0 toggle code is compiled unconditionally and\nreaches br_fdb_delete_locals_per_vlan_port() and\nbr_fdb_insert_locals_per_vlan_port(), where the NULL vlan group pointer\nis dereferenced via list_for_each_entry(v, \u0026vg-\u003evlan_list, vlist).\n\nThe observed crash is in the delete path, triggered when creating a\nbridge with IFLA_BR_MULTI_BOOLOPT containing BR_BOOLOPT_FDB_LOCAL_VLAN_0\nvia RTM_NEWLINK. The insert helper has the same bug pattern.\n\n  Oops: general protection fault, probably for non-canonical address 0xdffffc0000000056: 0000 [#1] KASAN NOPTI\n  KASAN: null-ptr-deref in range [0x00000000000002b0-0x00000000000002b7]\n  RIP: 0010:br_fdb_delete_locals_per_vlan+0x2b9/0x310\n  Call Trace:\n   br_fdb_toggle_local_vlan_0+0x452/0x4c0\n   br_toggle_fdb_local_vlan_0+0x31/0x80 net/bridge/br.c:276\n   br_boolopt_toggle net/bridge/br.c:313\n   br_boolopt_multi_toggle net/bridge/br.c:364\n   br_changelink net/bridge/br_netlink.c:1542\n   br_dev_newlink net/bridge/br_netlink.c:1575\n\nAdd NULL checks for the vlan group pointer in both helpers, returning\nearly when there are no VLANs to iterate. This matches the existing\npattern used by other bridge FDB functions such as br_fdb_add() and\nbr_fdb_delete()."
    }
  ],
  "id": "CVE-2026-43100",
  "lastModified": "2026-05-06T13:07:51.607",
  "metrics": {},
  "published": "2026-05-06T10:16:23.523",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1979645e1842cb7017525a61a0e0e0beb924d02a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ddf0ec2d600e7dad62b89692749534d7900a732a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/fb612d436ff0317659e45a91c25fd7d9516f5b1b"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}

GHSA-R5QW-5M8Q-6774

Vulnerability from github – Published: 2026-05-06 12:30 – Updated: 2026-05-06 12:30

Details

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

bridge: guard local VLAN-0 FDB helpers against NULL vlan group

When CONFIG_BRIDGE_VLAN_FILTERING is not set, br_vlan_group() and nbp_vlan_group() return NULL (br_private.h stub definitions). The BR_BOOLOPT_FDB_LOCAL_VLAN_0 toggle code is compiled unconditionally and reaches br_fdb_delete_locals_per_vlan_port() and br_fdb_insert_locals_per_vlan_port(), where the NULL vlan group pointer is dereferenced via list_for_each_entry(v, &vg->vlan_list, vlist).

The observed crash is in the delete path, triggered when creating a bridge with IFLA_BR_MULTI_BOOLOPT containing BR_BOOLOPT_FDB_LOCAL_VLAN_0 via RTM_NEWLINK. The insert helper has the same bug pattern.

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000056: 0000 [#1] KASAN NOPTI KASAN: null-ptr-deref in range [0x00000000000002b0-0x00000000000002b7] RIP: 0010:br_fdb_delete_locals_per_vlan+0x2b9/0x310 Call Trace: br_fdb_toggle_local_vlan_0+0x452/0x4c0 br_toggle_fdb_local_vlan_0+0x31/0x80 net/bridge/br.c:276 br_boolopt_toggle net/bridge/br.c:313 br_boolopt_multi_toggle net/bridge/br.c:364 br_changelink net/bridge/br_netlink.c:1542 br_dev_newlink net/bridge/br_netlink.c:1575

Add NULL checks for the vlan group pointer in both helpers, returning early when there are no VLANs to iterate. This matches the existing pattern used by other bridge FDB functions such as br_fdb_add() and br_fdb_delete().

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-43100"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-06T10:16:23Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbridge: guard local VLAN-0 FDB helpers against NULL vlan group\n\nWhen CONFIG_BRIDGE_VLAN_FILTERING is not set, br_vlan_group() and\nnbp_vlan_group() return NULL (br_private.h stub definitions). The\nBR_BOOLOPT_FDB_LOCAL_VLAN_0 toggle code is compiled unconditionally and\nreaches br_fdb_delete_locals_per_vlan_port() and\nbr_fdb_insert_locals_per_vlan_port(), where the NULL vlan group pointer\nis dereferenced via list_for_each_entry(v, \u0026vg-\u003evlan_list, vlist).\n\nThe observed crash is in the delete path, triggered when creating a\nbridge with IFLA_BR_MULTI_BOOLOPT containing BR_BOOLOPT_FDB_LOCAL_VLAN_0\nvia RTM_NEWLINK. The insert helper has the same bug pattern.\n\n  Oops: general protection fault, probably for non-canonical address 0xdffffc0000000056: 0000 [#1] KASAN NOPTI\n  KASAN: null-ptr-deref in range [0x00000000000002b0-0x00000000000002b7]\n  RIP: 0010:br_fdb_delete_locals_per_vlan+0x2b9/0x310\n  Call Trace:\n   br_fdb_toggle_local_vlan_0+0x452/0x4c0\n   br_toggle_fdb_local_vlan_0+0x31/0x80 net/bridge/br.c:276\n   br_boolopt_toggle net/bridge/br.c:313\n   br_boolopt_multi_toggle net/bridge/br.c:364\n   br_changelink net/bridge/br_netlink.c:1542\n   br_dev_newlink net/bridge/br_netlink.c:1575\n\nAdd NULL checks for the vlan group pointer in both helpers, returning\nearly when there are no VLANs to iterate. This matches the existing\npattern used by other bridge FDB functions such as br_fdb_add() and\nbr_fdb_delete().",
  "id": "GHSA-r5qw-5m8q-6774",
  "modified": "2026-05-06T12:30:27Z",
  "published": "2026-05-06T12:30:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43100"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1979645e1842cb7017525a61a0e0e0beb924d02a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ddf0ec2d600e7dad62b89692749534d7900a732a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fb612d436ff0317659e45a91c25fd7d9516f5b1b"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

CVE-2026-43100 (GCVE-0-2026-43100)

FKIE_CVE-2026-43100

GHSA-R5QW-5M8Q-6774

Tags

Sightings

Nomenclature