{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "cdae7c07e3e3509eaabc18c1640a55dc5b99c179"
            },
            {
              "fixed": "37abc4504fa19d8f9f1e87792e8a2b8fdb308e40"
            },
            {
              "fixed": "e2d4d51cf5785815fa4e91e0c019e3eb2506a84c"
            },
            {
              "fixed": "de618299190b418291609e6921557253bd417e25"
            },
            {
              "fixed": "5506c825f14d810f0690b1f4367cb7249ebb387a"
            },
            {
              "fixed": "542a13890b742099c461d70920e97b14e568f6ec"
            },
            {
              "fixed": "d548179adcc87e1bc66b17e00352a1f536e76065"
            },
            {
              "fixed": "3bec49ca55e08fb085cc4318f24b1b37eaab28cb"
            },
            {
              "fixed": "de21b59c29e31c5108ddc04210631bbfab81b997"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.15.0"
            },
            {
              "fixed": "5.10.259"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.210"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.176"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.143"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.93"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.35"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.0.12"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63892.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nthunderbolt: property: Reject dir_len \u003c 4 to prevent size_t underflow\n\nOn the non-root path, __tb_property_parse_dir() takes dir_len from\nentry-\u003elength (u16 widened to size_t).  Two distinct OOB conditions\nfollow when entry-\u003elength \u003c 4:\n\n1. The non-root path begins with kmemdup(\u0026block[dir_offset],\n   sizeof(*dir-\u003euuid), ...) which always reads 4 dwords from\n   dir_offset.  tb_property_entry_valid() only enforces\n   dir_offset + entry-\u003elength \u003c= block_len, so a crafted entry\n   with dir_offset close to the end of the property block and\n   entry-\u003elength 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 \u003c 4 on the non-root path *before* the UUID kmemdup,\nwhich closes both holes.\n\nAlso move INIT_LIST_HEAD(\u0026dir-\u003eproperties) 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.",
  "id": "CVE-2026-63892",
  "modified": "2026-07-21T03:41:52.342639068Z",
  "published": "2026-07-19T14:55:03.568Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/37abc4504fa19d8f9f1e87792e8a2b8fdb308e40"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3bec49ca55e08fb085cc4318f24b1b37eaab28cb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/542a13890b742099c461d70920e97b14e568f6ec"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5506c825f14d810f0690b1f4367cb7249ebb387a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d548179adcc87e1bc66b17e00352a1f536e76065"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/de21b59c29e31c5108ddc04210631bbfab81b997"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/de618299190b418291609e6921557253bd417e25"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e2d4d51cf5785815fa4e91e0c019e3eb2506a84c"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63892.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63892"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.8.0",
  "summary": "thunderbolt: property: Reject dir_len \u003c 4 to prevent size_t underflow"
}