CVE-2026-63891 (GCVE-0-2026-63891)
Vulnerability from cvelistv5
Published
2026-07-19 14:55
Modified
2026-07-19 14:55
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: thunderbolt: property: Cap recursion depth in __tb_property_parse_dir() A DIRECTORY entry's value field is used as the dir_offset for a recursive call into __tb_property_parse_dir() with no depth counter. A crafted peer that chains DIRECTORY entries into a back-reference loop drives the parser until the kernel stack is exhausted and the guard page fires. Any untrusted XDomain peer (cable, dock, in-line inspector, adjacent host) that reaches the PROPERTIES_REQUEST control-plane exchange can trigger this without authentication. Thread a depth counter through tb_property_parse() and __tb_property_parse_dir(), and reject blocks that exceed TB_PROPERTY_MAX_DEPTH = 8. That is comfortably larger than any observed legitimate XDomain layout. Operators who do not need XDomain host-to-host discovery can disable the path entirely with thunderbolt.xdomain=0 on the kernel command line.
References
Impacted products
Vendor Product Version
Linux Linux Version: cdae7c07e3e3509eaabc18c1640a55dc5b99c179
Version: cdae7c07e3e3509eaabc18c1640a55dc5b99c179
Version: cdae7c07e3e3509eaabc18c1640a55dc5b99c179
Version: cdae7c07e3e3509eaabc18c1640a55dc5b99c179
Version: cdae7c07e3e3509eaabc18c1640a55dc5b99c179
Version: cdae7c07e3e3509eaabc18c1640a55dc5b99c179
Version: cdae7c07e3e3509eaabc18c1640a55dc5b99c179
Version: cdae7c07e3e3509eaabc18c1640a55dc5b99c179
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{
  "containers": {
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/thunderbolt/property.c"
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          "vendor": "Linux",
          "versions": [
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              "versionType": "original_commit_for_fix"
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      ],
      "cpeApplicability": [
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          "nodes": [
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              "negate": false,
              "operator": "OR"
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      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nthunderbolt: property: Cap recursion depth in __tb_property_parse_dir()\n\nA DIRECTORY entry\u0027s value field is used as the dir_offset for a\nrecursive call into __tb_property_parse_dir() with no depth counter.\nA crafted peer that chains DIRECTORY entries into a back-reference\nloop drives the parser until the kernel stack is exhausted and the\nguard page fires.  Any untrusted XDomain peer (cable, dock, in-line\ninspector, adjacent host) that reaches the PROPERTIES_REQUEST\ncontrol-plane exchange can trigger this without authentication.\n\nThread a depth counter through tb_property_parse() and\n__tb_property_parse_dir(), and reject blocks that exceed\nTB_PROPERTY_MAX_DEPTH = 8.  That is comfortably larger than any\nobserved legitimate XDomain layout.\n\nOperators who do not need XDomain host-to-host discovery can disable\nthe path entirely with thunderbolt.xdomain=0 on the kernel command\nline."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-19T14:55:02.840Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/2b5f47a710172c962ef42d1b732b04d2ad0dce21"
        },
        {
          "url": "https://git.kernel.org/stable/c/95839a67ea56ca35732aad7f711404a3127cfe2d"
        },
        {
          "url": "https://git.kernel.org/stable/c/0a84ab9271936c11e84e511bb52fc5682f8b6726"
        },
        {
          "url": "https://git.kernel.org/stable/c/b4621e5ef63405c317a84b711faf3bd75b3c6a94"
        },
        {
          "url": "https://git.kernel.org/stable/c/f31c6d220f455b5af63590302b30e1b932d14599"
        },
        {
          "url": "https://git.kernel.org/stable/c/830c8a9b467e7d3a158483d37fa7dc13892b293a"
        },
        {
          "url": "https://git.kernel.org/stable/c/ed9455ef4bd9babc90f92e526abe3fb68c1a8709"
        },
        {
          "url": "https://git.kernel.org/stable/c/928abe19fbf0127003abcb1ea69cabc1c897d0ab"
        }
      ],
      "title": "thunderbolt: property: Cap recursion depth in __tb_property_parse_dir()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-63891",
    "datePublished": "2026-07-19T14:55:02.840Z",
    "dateReserved": "2026-07-19T07:54:57.019Z",
    "dateUpdated": "2026-07-19T14:55:02.840Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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