ntfs3: cap RESTART_TABLE free-chain walker at rt->used

{
  "id": "30ef585ba9ddca3116f76b184f391201593d36f7e87f9120d6e9aa0b267a7fcb",
  "url": "https://osv.dev/vulnerability/CVE-2026-72193",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ntfs3: cap RESTART_TABLE free-chain walker at rt->used",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ntfs3: cap RESTART_TABLE free-chain walker at rt->used A crafted NTFS3 disk image triggers an in-kernel infinite loop at mount time, hanging the mounting thread and firing the soft-lockup watchdog within ~22s on multi-CPU hosts (panic with kernel.softlockup_panic=1). The bug is reachable from desktop USB auto-mount on distributions where udisks2 routes the NTFS signature to the in-tree ntfs3 driver (Arch family and an increasing fraction of Fedora / openSUSE / RHEL deployments); CAP_SYS_ADMIN-class manual mount elsewhere. check_rstbl()'s second walker iterates the free-entry singly-linked list headed by rt->first_free with no upper bound on iteration count: for (off = ff; off;) { if (off == RESTART_ENTRY_ALLOCATED) return false; off = le32_to_cpu(*(__le32 *)Add2Ptr(rt, off)); if (off > ts - sizeof(__le32)) return false; } The existing guards cover three exits: end-of-list (off == 0), the in-use marker (off == RESTART_ENTRY_ALLOCATED), and out-of-bounds (off > ts - sizeof(__le32)). None of the three prevents an in-bounds cycle. A crafted on-disk RESTART_TABLE whose free chain contains a self-loop or A->B->A cycle whose offsets satisfy: - in range [sizeof(struct RESTART_TABLE), ts - sizeof(__le32)] - (off - sizeof(struct RESTART_TABLE)) % rsize == 0 passes all existing guards and spins the mount-time thread forever. Reproduced in UML by hand-forging a 2 MB NTFS3 image whose journal RESTART_TABLE first_free = 0x",
    "evidence": "osv:CVE-2026-72193",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.15.212",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.178",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.145",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.97",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.40",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.1.5",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-72193",
      "aliases": [
        "CVE-2026-72193"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                {
                  "fixed": "8128bec895075253c779d67afdc90ae513265fca"
                },
                {
                  "fixed": "7972df425687daa70d971fe6ed415e78683133dd"
                },
                {
                  "fixed": "7ac4c86915c24c208a0f0611b71d9676686fe756"
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                {
                  "fixed": "29b86dbe88cbbef53bb9aaec2e279359f8c450f8"
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                {
                  "fixed": "0fad25687d4d3fa1fdd313d31b9cb5817c425029"
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                {
                  "fixed": "d313416280d41bea272f02a6034dfa88008692a0"
                },
                {
                  "fixed": "9611f644302c07d21bc8af97e3e06a3d30064253"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72193.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.15.0"
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                {
                  "fixed": "5.15.212"
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              "type": "ECOSYSTEM",
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                  "introduced": "5.16.0"
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                {
                  "fixed": "6.1.178"
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                {
                  "introduced": "6.2.0"
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                {
                  "fixed": "6.6.145"
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              ]
            },
            {
              "type": "ECOSYSTEM",
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                  "introduced": "6.7.0"
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                {
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            {
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                  "introduced": "6.13.0"
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            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.1.5"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72193.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:31.682404004Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/0fad25687d4d3fa1fdd313d31b9cb5817c425029",
        "https://git.kernel.org/stable/c/29b86dbe88cbbef53bb9aaec2e279359f8c450f8",
        "https://git.kernel.org/stable/c/7972df425687daa70d971fe6ed415e78683133dd",
        "https://git.kernel.org/stable/c/7ac4c86915c24c208a0f0611b71d9676686fe756",
        "https://git.kernel.org/stable/c/8128bec895075253c779d67afdc90ae513265fca",
        "https://git.kernel.org/stable/c/9611f644302c07d21bc8af97e3e06a3d30064253",
        "https://git.kernel.org/stable/c/d313416280d41bea272f02a6034dfa88008692a0",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72193.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-72193",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72193.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-72193",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 498730,
  "published_at": "2026-08-15T05:53:53.381+00:00"
}