{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-31622",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-31622"
  ],
  "published": "2026-04-24T14:43:40Z",
  "summary": "NFC: digital: Bounds check NFC-A cascade depth in SDD response handler",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFC: digital: Bounds check NFC-A cascade depth in SDD response handler\n\nThe NFC-A anti-collision cascade in digital_in_recv_sdd_res() appends 3\nor 4 bytes to target->nfcid1 on each round, but the number of cascade\nrounds is controlled entirely by the peer device.  The peer sets the\ncascade tag in the SDD_RES (deciding 3 vs 4 bytes) and the\ncascade-incomplete bit in the SEL_RES (deciding whether another round\nfollows).\n\nISO 14443-3 limits NFC-A to three cascade levels and target->nfcid1 is\nsized accordingly (NFC_NFCID1_MAXSIZE = 10), but nothing in the driver\nactually enforces this.  This means a malicious peer can keep the\ncascade running, writing past the heap-allocated nfc_target with each\nround.\n\nFix this by rejecting the response when the accumulated UID would exceed\nthe buffer.\n\nCommit e329e71013c9 (\"NFC: nci: Bounds check struct nfc_target arrays\")\nfixed similar missing checks against the same field on the NCI path.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:A/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-2026-31622"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9ba6bb09e00b922d902f684f575779e5433fe6e3"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/f83b399aa05a0712e3b1569a30d3d90b3533d2ef"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/20663102c14566e900e1d2f679e30b7f1694f387"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/2819f34e08bdffb6f06a51c67948ec5737fb166a"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/1bec5698b55aa2be5c3b983dba657c01d0fd3dbc"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/5a59bf70c38ee1eb4be03bab830bbc3a6f0bd1f1"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/8d9d9bf3565271ca7ab9c716a94e87296177e7ba"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/cc024a3de265ef6c58957f4990eccb9f806208cb"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/46ce8be2ced389bccd84bcc04a12cf2f4d0c22d1"
    }
  ],
  "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": 8.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:A - The vulnerable code processes NFC-A anti-collision responses from a peer/tag in the local NFC RF field, so the attacker must be within NFC proximity rather than on an IP network.\nAC:L - The peer controls both the cascade tag in SDD_RES and the cascade-incomplete bit in SEL_RES, and can repeat valid BCC/CRC responses to drive the overflow without a race or unusual memory state.\nPR:N - The malicious NFC peer does not need local credentials or kernel privileges; any local CAP_NET_ADMIN requirement only applies to the victim system component that starts polling.\nUI:N - In a reasonable high-impact deployment such as an NFC reader, kiosk, or access-control device, polling is already active and the attacker only needs to present the malicious NFC peer.\nS:U - The corruption occurs in the host kernel NFC stack and impacts the same kernel security authority, with no VM, IOMMU, or separate sandbox boundary crossed.\nC:H - This is a peer-controlled heap out-of-bounds write past struct nfc_target, and such kernel memory corruption is defensibly exploitable for information disclosure or arbitrary memory access.\nI:H - The bug writes attacker-controlled NFCID bytes beyond the fixed nfcid1 buffer and can continue across cascade rounds, making kernel memory corruption and control-flow/data integrity compromise plausible.\nA:H - Even without full exploitation, overflowing a heap-allocated kernel object from NFC response handling can corrupt adjacent state and cause an oops, panic, or persistent crash."
    }
  }
}