net: vlan: fix VLAN 0 refcount imbalance of toggling filtering during runtime

{
  "id": "e4107d5a365ec331d26a58391a0b7b78a7543527c7cdd1da5beebf82194fafa0",
  "url": "https://osv.dev/vulnerability/CVE-2025-38470",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "net: vlan: fix VLAN 0 refcount imbalance of toggling filtering during runtime",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: net: vlan: fix VLAN 0 refcount imbalance of toggling filtering during runtime Assuming the \"rx-vlan-filter\" feature is enabled on a net device, the 8021q module will automatically add or remove VLAN 0 when the net device is put administratively up or down, respectively. There are a couple of problems with the above scheme. The first problem is a memory leak that can happen if the \"rx-vlan-filter\" feature is disabled while the device is running: # ip link add bond1 up type bond mode 0 # ethtool -K bond1 rx-vlan-filter off # ip link del dev bond1 When the device is put administratively down the \"rx-vlan-filter\" feature is disabled, so the 8021q module will not remove VLAN 0 and the memory will be leaked [1]. Another problem that can happen is that the kernel can automatically delete VLAN 0 when the device is put administratively down despite not adding it when the device was put administratively up since during that time the \"rx-vlan-filter\" feature was disabled. null-ptr-unref or bug_on[2] will be triggered by unregister_vlan_dev() for refcount imbalance if toggling filtering during runtime: $ ip link add bond0 type bond mode 0 $ ip link add link bond0 name vlan0 type vlan id 0 protocol 802.1q $ ethtool -K bond0 rx-vlan-filter off $ ifconfig bond0 up $ ethtool -K bond0 rx-vlan-filter on $ ifconfig bond0 down $ ip link del vlan0 Root cause is as below: step1: add vlan0 for real_dev, such as bond, team. register",
    "evidence": "osv:CVE-2025-38470",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.4.297",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.10.241",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.190",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.147",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.100",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.40",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.15.8",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2025-38470",
      "aliases": [
        "CVE-2025-38470"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "ad1afb00393915a51c21b1ae8704562bf036855f"
                },
                {
                  "fixed": "ba48d3993af23753e1f1f01c8d592de9c7785f24"
                },
                {
                  "fixed": "35142b3816832889e50164d993018ea5810955ae"
                },
                {
                  "fixed": "047b61a24d7c866c502aeeea482892969a68f216"
                },
                {
                  "fixed": "d43ef15bf4856c8c4c6c3572922331a5f06deb77"
                },
                {
                  "fixed": "bb515c41306454937464da055609b5fb0a27821b"
                },
                {
                  "fixed": "8984bcbd1edf5bee5be06ad771d157333b790c33"
                },
                {
                  "fixed": "93715aa2d80e6c5cea1bb486321fc4585076928b"
                },
                {
                  "fixed": "579d4f9ca9a9a605184a9b162355f6ba131f678d"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-38470.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "2.6.36"
                },
                {
                  "fixed": "5.4.297"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.5.0"
                },
                {
                  "fixed": "5.10.241"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.11.0"
                },
                {
                  "fixed": "5.15.190"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.147"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.6.100"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.40"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.15.8"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-38470.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:51.330970770Z",
      "provider": "osv",
      "references": [
        "https://cert-portal.siemens.com/productcert/html/ssa-082556.html",
        "https://git.kernel.org/stable/c/047b61a24d7c866c502aeeea482892969a68f216",
        "https://git.kernel.org/stable/c/35142b3816832889e50164d993018ea5810955ae",
        "https://git.kernel.org/stable/c/579d4f9ca9a9a605184a9b162355f6ba131f678d",
        "https://git.kernel.org/stable/c/8984bcbd1edf5bee5be06ad771d157333b790c33",
        "https://git.kernel.org/stable/c/93715aa2d80e6c5cea1bb486321fc4585076928b",
        "https://git.kernel.org/stable/c/ba48d3993af23753e1f1f01c8d592de9c7785f24",
        "https://git.kernel.org/stable/c/bb515c41306454937464da055609b5fb0a27821b",
        "https://git.kernel.org/stable/c/d43ef15bf4856c8c4c6c3572922331a5f06deb77",
        "https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html",
        "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/38xxx/CVE-2025-38470.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-38470",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/38xxx/CVE-2025-38470.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-38470",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 519641,
  "published_at": "2025-07-28T11:21:32.002+00:00"
}