GHSA-Q8VR-48QG-6QFP

Vulnerability from github – Published: 2026-09-16 09:30 – Updated: 2026-09-16 15:30
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

fs/ntfs3: reject restart table growth beyond U16_MAX entries

During $LogFile replay, log_replay() indexes the transaction table by the transact_id taken from the log record header. check_log_rec() only verifies that transact_id is non-zero and properly aligned, not its magnitude, so a crafted image can request an arbitrarily large index.

alloc_rsttbl_from_idx() grows the table to cover that index via extend_rsttbl(), which passes the new entry count to init_rsttbl():

rt = init_rsttbl(esize, used + add);

used + add is computed as u32 but init_rsttbl() takes a u16, and the count is stored in struct RESTART_TABLE as a __le16. When used + add exceeds U16_MAX it is truncated, init_rsttbl() allocates a table far smaller than the index requires, and alloc_rsttbl_from_idx() then dereferences and writes at the original, untruncated offset -- an out-of-bounds access past the allocation, reachable by mounting a crafted NTFS image.

BUG: KASAN: use-after-free in alloc_rsttbl_from_idx (fs/ntfs3/fslog.c:950) Read of size 4 at addr ffff8880327ffff8 by task exploit alloc_rsttbl_from_idx (fs/ntfs3/fslog.c:950) log_replay (fs/ntfs3/fslog.c:4562) ntfs_loadlog_and_replay (fs/ntfs3/fsntfs.c:324) ntfs_fill_super (fs/ntfs3/super.c:1393) get_tree_bdev_flags vfs_get_tree path_mount __x64_sys_mount

A restart table is limited to U16_MAX entries by its __le16 count, so a larger growth request is invalid input. Reject it in extend_rsttbl(); all callers already handle a NULL return.

Severity
8.4 (High)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-89782"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-16T09:17:08Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/ntfs3: reject restart table growth beyond U16_MAX entries\n\nDuring $LogFile replay, log_replay() indexes the transaction table by the\ntransact_id taken from the log record header.  check_log_rec() only\nverifies that transact_id is non-zero and properly aligned, not its\nmagnitude, so a crafted image can request an arbitrarily large index.\n\nalloc_rsttbl_from_idx() grows the table to cover that index via\nextend_rsttbl(), which passes the new entry count to init_rsttbl():\n\n\trt = init_rsttbl(esize, used + add);\n\nused + add is computed as u32 but init_rsttbl() takes a u16, and the\ncount is stored in struct RESTART_TABLE as a __le16.  When used + add\nexceeds U16_MAX it is truncated, init_rsttbl() allocates a table far\nsmaller than the index requires, and alloc_rsttbl_from_idx() then\ndereferences and writes at the original, untruncated offset -- an\nout-of-bounds access past the allocation, reachable by mounting a\ncrafted NTFS image.\n\n BUG: KASAN: use-after-free in alloc_rsttbl_from_idx (fs/ntfs3/fslog.c:950)\n Read of size 4 at addr ffff8880327ffff8 by task exploit\n  alloc_rsttbl_from_idx (fs/ntfs3/fslog.c:950)\n  log_replay (fs/ntfs3/fslog.c:4562)\n  ntfs_loadlog_and_replay (fs/ntfs3/fsntfs.c:324)\n  ntfs_fill_super (fs/ntfs3/super.c:1393)\n  get_tree_bdev_flags\n  vfs_get_tree\n  path_mount\n  __x64_sys_mount\n\nA restart table is limited to U16_MAX entries by its __le16 count, so a\nlarger growth request is invalid input.  Reject it in extend_rsttbl();\nall callers already handle a NULL return.",
  "id": "GHSA-q8vr-48qg-6qfp",
  "modified": "2026-09-16T15:30:57Z",
  "published": "2026-09-16T09:30:30Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89782"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/111f8d74a19d85942ecbb3aba78f6f3c88e59391"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/339e59996ff193adcf1c438cf05f19e753beb3a7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/967a5ff8a614d10126b6d46db1ac040948d6cb42"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/aad605a450611e2a7b7cf9dd5724004d39192bfb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/be218a01aadffe33ed4fc73e25276d676ebbd09d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/caa0ec3fc44a13d7c21d78e4722f4f05f87ccf56"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ecde45cd81dc28f5696c312c5ce5a509962e9ab1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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