{
  "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-2026-81000",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-81000",
    "idYear": 2026,
    "status": "PUBLISHED",
    "publishedAt": "2026-09-11T19:42:54.181Z",
    "updatedAt": "2026-10-19T08:46:24.640Z",
    "importedAt": "2026-10-24T01:58:30.346Z",
    "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: tun: bound receive headroom",
      "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: tun: bound receive headroom\n\ntun_get_user() uses tun->align both as skb headroom and when choosing how\nmuch packet data to keep linear. OVS can propagate an oversized headroom\nrequest from another port to TUN or TAP.\n\nWhen align is larger than the usable space in a one-page skb head,\nSKB_MAX_HEAD(align) underflows and the result becomes negative when stored\nin good_linear. That value later wraps when assigned to the size_t linear\nvariable, and tun_alloc_skb() can place skb->data outside the allocated\nhead.\n\nBound the headroom stored by TUN to the one-page skb-head budget and the\nlargest non-sentinel 16-bit skb header offset. Leave one linear byte for\nraw TUN and a complete Ethernet header for TAP, including NET_IP_ALIGN.\n\nAlso pull the raw-TUN protocol byte and the TAP Ethernet header before\naccessing them, so these checks remain safe for nonlinear skbs supplied by\nother allocation paths.",
      "affected": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "eaea34b23c46bf17b4a5638be69ab3561854f34b",
              "status": "affected",
              "versionType": "git",
              "lessThan": "ad715e713610d2d5473c3a6498c825ccecf26491"
            },
            {
              "version": "eaea34b23c46bf17b4a5638be69ab3561854f34b",
              "status": "affected",
              "versionType": "git",
              "lessThan": "708e87937de93f445225c134a2e20519f9b4ce60"
            },
            {
              "version": "eaea34b23c46bf17b4a5638be69ab3561854f34b",
              "status": "affected",
              "versionType": "git",
              "lessThan": "18ef24cdb2eba32e38f1d27f2d02b7b4212e8f76"
            },
            {
              "version": "eaea34b23c46bf17b4a5638be69ab3561854f34b",
              "status": "affected",
              "versionType": "git",
              "lessThan": "010eee265d6bd8769b6a523d2a0693d9b3f5df43"
            },
            {
              "version": "eaea34b23c46bf17b4a5638be69ab3561854f34b",
              "status": "affected",
              "versionType": "git",
              "lessThan": "379d85c7f25f3e05a428225e6b8a65613c6e9b9d"
            },
            {
              "version": "eaea34b23c46bf17b4a5638be69ab3561854f34b",
              "status": "affected",
              "versionType": "git",
              "lessThan": "e098d9cc8859614a7f7baebc96e32a5a16b18ed2"
            },
            {
              "version": "eaea34b23c46bf17b4a5638be69ab3561854f34b",
              "status": "affected",
              "versionType": "git",
              "lessThan": "0ada54ea63e48b9c1608e917ccb7dfadbe86db28"
            },
            {
              "version": "eaea34b23c46bf17b4a5638be69ab3561854f34b",
              "status": "affected",
              "versionType": "git",
              "lessThan": "447c9303942c439a117d9b76ce6d6e2116b38ee7"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "versions": [
            {
              "version": "4.6",
              "status": "affected"
            },
            {
              "version": "0",
              "status": "unaffected",
              "versionType": "semver",
              "lessThan": "4.6"
            },
            {
              "version": "5.10.270",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "version": "5.15.221",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "version": "6.1.188",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "version": "6.6.157",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "version": "6.12.109",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "version": "6.18.50",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "version": "7.2.4",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "version": "7.3",
              "status": "unaffected",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ]
    }
  }
}