netfilter: nfnetlink_log: fix uninitialized padding leak in NFULA_PAYLOAD

{
  "id": "6ee79709a62d1c4f2e06634e63d77dece888271b46b70077f11720874edce779",
  "url": "https://osv.dev/vulnerability/CVE-2026-31428",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "netfilter: nfnetlink_log: fix uninitialized padding leak in NFULA_PAYLOAD",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: netfilter: nfnetlink_log: fix uninitialized padding leak in NFULA_PAYLOAD __build_packet_message() manually constructs the NFULA_PAYLOAD netlink attribute using skb_put() and skb_copy_bits(), bypassing the standard nla_reserve()/nla_put() helpers. While nla_total_size(data_len) bytes are allocated (including NLA alignment padding), only data_len bytes of actual packet data are copied. The trailing nla_padlen(data_len) bytes (1-3 when data_len is not 4-byte aligned) are never initialized, leaking stale heap contents to userspace via the NFLOG netlink socket. Replace the manual attribute construction with nla_reserve(), which handles the tailroom check, header setup, and padding zeroing via __nla_reserve(). The subsequent skb_copy_bits() fills in the payload data on top of the properly initialized attribute.",
    "evidence": "osv:CVE-2026-31428",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
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            "value": "5.10.253",
            "evidence": "/affected/1/ranges"
          },
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            "value": "5.15.203",
            "evidence": "/affected/1/ranges"
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            "value": "6.1.168",
            "evidence": "/affected/1/ranges"
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          {
            "value": "6.18.21",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.19.11",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-31428",
      "aliases": [
        "CVE-2026-31428"
      ],
      "affected": [
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                  "fixed": "21d8efda029948d3666b0db5afcc0d36c0984aae"
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                {
                  "fixed": "fc961dd7272b5e4a462999635e44a4770d7f2482"
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                {
                  "fixed": "a8365d1064ded323797c5e28e91070c52f44b76c"
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                {
                  "fixed": "a2f6ff3444b663d6cfa63eadd61327a18592885a"
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                  "fixed": "c9f6c51d36482805ac3ffadb9663fe775a13e926"
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          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
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          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-31428.json"
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      ],
      "modified": "2026-10-28T02:30:30.955660860Z",
      "provider": "osv",
      "references": [
        "https://cert-portal.siemens.com/productcert/html/ssa-019113.html",
        "https://cert-portal.siemens.com/productcert/html/ssa-082556.html",
        "https://cert-portal.siemens.com/productcert/html/ssa-457936.html",
        "https://git.kernel.org/stable/c/21d8efda029948d3666b0db5afcc0d36c0984aae",
        "https://git.kernel.org/stable/c/52025ebaa29f4eb4ed8bf92ce83a68f24ab7fdf7",
        "https://git.kernel.org/stable/c/7eff72968161fb8ddb26113344de3b92fb7d7ef5",
        "https://git.kernel.org/stable/c/7f3e5d72455936f42709116fabeca3bb216cda62",
        "https://git.kernel.org/stable/c/a2f6ff3444b663d6cfa63eadd61327a18592885a",
        "https://git.kernel.org/stable/c/a8365d1064ded323797c5e28e91070c52f44b76c",
        "https://git.kernel.org/stable/c/c9f6c51d36482805ac3ffadb9663fe775a13e926",
        "https://git.kernel.org/stable/c/fc961dd7272b5e4a462999635e44a4770d7f2482",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31428.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-31428",
        "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/2026/31xxx/CVE-2026-31428.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-31428",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 497935,
  "published_at": "2026-04-13T13:40:30.987+00:00"
}