{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2021-47223",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2021-47223",
    "idYear": 2021,
    "status": "PUBLISHED",
    "publishedAt": "2024-05-21T14:19:28.882Z",
    "updatedAt": "2026-05-11T13:50:20.666Z",
    "importedAt": "2026-10-24T01:56:36.661Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": "net: bridge: fix vlan tunnel dst null pointer dereference",
      "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: bridge: fix vlan tunnel dst null pointer dereference\n\nThis patch fixes a tunnel_dst null pointer dereference due to lockless\naccess in the tunnel egress path. When deleting a vlan tunnel the\ntunnel_dst pointer is set to NULL without waiting a grace period (i.e.\nwhile it's still usable) and packets egressing are dereferencing it\nwithout checking. Use READ/WRITE_ONCE to annotate the lockless use of\ntunnel_id, use RCU for accessing tunnel_dst and make sure it is read\nonly once and checked in the egress path. The dst is already properly RCU\nprotected so we don't need to do anything fancy than to make sure\ntunnel_id and tunnel_dst are read only once and checked in the egress path.",
      "affected": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "11538d039ac6efcf4f1a6c536e1b87cd3668a9fd",
              "status": "affected",
              "versionType": "git",
              "lessThan": "ad7feefe7164892db424c45687472db803d87f79"
            },
            {
              "version": "11538d039ac6efcf4f1a6c536e1b87cd3668a9fd",
              "status": "affected",
              "versionType": "git",
              "lessThan": "24a6e55f17aa123bc1fc54b7d3c410b41bc16530"
            },
            {
              "version": "11538d039ac6efcf4f1a6c536e1b87cd3668a9fd",
              "status": "affected",
              "versionType": "git",
              "lessThan": "a2241e62f6b4a774d8a92048fdf59c45f6c2fe5c"
            },
            {
              "version": "11538d039ac6efcf4f1a6c536e1b87cd3668a9fd",
              "status": "affected",
              "versionType": "git",
              "lessThan": "fe0448a3fad365a747283a00a1d1ad5e8d6675b7"
            },
            {
              "version": "11538d039ac6efcf4f1a6c536e1b87cd3668a9fd",
              "status": "affected",
              "versionType": "git",
              "lessThan": "abb02e05cb1c0a30dd873a29f33bc092067dc35d"
            },
            {
              "version": "11538d039ac6efcf4f1a6c536e1b87cd3668a9fd",
              "status": "affected",
              "versionType": "git",
              "lessThan": "58e2071742e38f29f051b709a5cca014ba51166f"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "versions": [
            {
              "version": "4.11",
              "status": "affected"
            },
            {
              "version": "0",
              "status": "unaffected",
              "versionType": "semver",
              "lessThan": "4.11"
            },
            {
              "version": "4.14.238",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "4.14.*"
            },
            {
              "version": "4.19.196",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "4.19.*"
            },
            {
              "version": "5.4.128",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.4.*"
            },
            {
              "version": "5.10.46",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "version": "5.12.13",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.12.*"
            },
            {
              "version": "5.13",
              "status": "unaffected",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ]
    }
  }
}