{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-64047",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-64047"
  ],
  "published": "2026-07-19T15:41:06Z",
  "summary": "net: tls: fix off-by-one in sg_chain entry count for wrapped sk_msg ring",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: tls: fix off-by-one in sg_chain entry count for wrapped sk_msg ring\n\nWhen an sk_msg scatterlist ring wraps (sg.end < sg.start),\ntls_push_record() chains the tail portion of the ring to the head\nusing sg_chain(). An extra entry in the sg array is reserved for\nthis:\n\n  struct sk_msg_sg {\n        [...]\n        /* The extra two elements:\n         * 1) used for chaining the front and sections when the list becomes\n         *    partitioned (e.g. end < start). The crypto APIs require the\n         *    chaining;\n         * 2) to chain tailer SG entries after the message.\n         */\n        struct scatterlist              data[MAX_MSG_FRAGS + 2];\n\nThe current code uses MAX_SKB_FRAGS + 1 as the ring size:\n\n    sg_chain(&msg_pl->sg.data[msg_pl->sg.start],\n             MAX_SKB_FRAGS - msg_pl->sg.start + 1,\n             msg_pl->sg.data);\n\nThis places the chain pointer at\n\n  sg_chain(data[start], (MAX_SKB_FRAGS - msg_start + 1) .. =\n  &data[start] + (MAX_SKB_FRAGS - msg_start + 1) - 1 =\n  data[start + (MAX_SKB_FRAGS - start + 1) - 1] =\n  data[MAX_SKB_FRAGS]\n\ninstead of the true last entry. This is likely due to a \"race\" of\nthe commit under Fixes landing close to\ncommit 031097d9e079 (\"bpf: sk_msg, zap ingress queue on psock down\")\n\nConvert to ARRAY_SIZE and drop the data[start] / - start (as suggested\nby Sabrina).",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
    }
  ],
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.175",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-64047"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/73963a375885d5ccb7def39fd0b4f542e0f343dd"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/47110c3a9ac247b688657337f5981efcfcb240dc"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/84158c2997159df4a0d70cd9c46774512d32a522"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/131ef12057d92b77b636321b7849c69222405a97"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/66339b71f105e6f83e0da3b9583d95077534fe1d"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/eca989eab4b2599dcb02f72140a7c08f08838520"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/2fb0dc7e0099686c4e9d2732745d8a31b18c3628"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/285943c6e7ca309bbea84b253745154241d9788a"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T13:16:28Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 9.8,
      "cvss_v3_severity": "Critical",
      "scenario": "AV:N - The flaw is in kernel TLS (kTLS) software transmit encryption triggered when a TLS socket sends records; remote peers on established TLS connections drive this TX path through normal network I/O.\nAC:L - An attacker who controls connection traffic can reliably create the wrapped sk_msg ring state via BPF sockmap SK_MSG verdict helpers (push/pop/redirect) and then trigger record push on demand.\nPR:N - Exploitation requires no privileges on the target host beyond being a network peer on a kTLS socket with sockmap BPF already configured by the service; attacker capabilities are not needed on the victim system.\nUI:N - Triggering requires only automated server-side TLS transmit activity in response to network input, with no victim user action.\nS:U - Impact is kernel memory corruption and potential privilege escalation within the same kernel/host security boundary, not a cross-VM or sandbox escape by itself.\nC:H - Corrupting an active scatterlist entry causes the AEAD crypto path to follow an incorrect chain, enabling out-of-bounds kernel memory reads beyond intended plaintext buffers.\nI:H - The malformed scatterlist passed to crypto_aead_encrypt() can direct encryption I/O to wrong memory regions, providing an out-of-bounds write primitive exploitable for control-flow hijacking.\nA:H - Scatterlist corruption in the kernel crypto TX path can cause kernel oopses, panics, or fatal BUG conditions when invalid chain entries or page pointers are dereferenced."
    }
  }
}