{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-63892",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2026-63892"
  ],
  "published": "2026-07-19T14:56:29Z",
  "summary": "thunderbolt: property: Reject dir_len < 4 to prevent size_t underflow",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nthunderbolt: property: Reject dir_len < 4 to prevent size_t underflow\n\nOn the non-root path, __tb_property_parse_dir() takes dir_len from\nentry->length (u16 widened to size_t).  Two distinct OOB conditions\nfollow when entry->length < 4:\n\n1. The non-root path begins with kmemdup(&block[dir_offset],\n   sizeof(*dir->uuid), ...) which always reads 4 dwords from\n   dir_offset.  tb_property_entry_valid() only enforces\n   dir_offset + entry->length <= block_len, so a crafted entry\n   with dir_offset close to the end of the property block and\n   entry->length in 0..3 passes that gate but lets the UUID copy\n   run off the block (e.g. dir_offset = 497, dir_len = 3 in a\n   500-dword block reads block[497..501]).\n\n2. After the kmemdup, content_len = dir_len - 4 underflows size_t\n   to ~SIZE_MAX, nentries becomes SIZE_MAX / 4, and the entry\n   walk runs OOB on each iteration until an entry fails\n   validation or the kernel oopses on an unmapped page.\n\nReject dir_len < 4 on the non-root path *before* the UUID kmemdup,\nwhich closes both holes.\n\nAlso move INIT_LIST_HEAD(&dir->properties) up to immediately after\nthe dir allocation so the new error-return path (and the existing\nuuid-alloc failure path) calling tb_property_free_dir() sees a\nwalkable list rather than the zero-initialized NULL next/prev that\nlist_for_each_entry_safe() would oops on.",
  "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": "6.1.176",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-63892"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/37abc4504fa19d8f9f1e87792e8a2b8fdb308e40"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/e2d4d51cf5785815fa4e91e0c019e3eb2506a84c"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/de618299190b418291609e6921557253bd417e25"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/5506c825f14d810f0690b1f4367cb7249ebb387a"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/542a13890b742099c461d70920e97b14e568f6ec"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/d548179adcc87e1bc66b17e00352a1f536e76065"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/3bec49ca55e08fb085cc4318f24b1b37eaab28cb"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/de21b59c29e31c5108ddc04210631bbfab81b997"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-07-19T14:56:29Z"
  }
}