FKIE_CVE-2025-71067

Vulnerability from fkie_nvd - Published: 2026-01-13 16:16 - Updated: 2026-01-14 16:26
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: ntfs: set dummy blocksize to read boot_block when mounting When mounting, sb->s_blocksize is used to read the boot_block without being defined or validated. Set a dummy blocksize before attempting to read the boot_block. The issue can be triggered with the following syz reproducer: mkdirat(0xffffffffffffff9c, &(0x7f0000000080)='./file1\x00', 0x0) r4 = openat$nullb(0xffffffffffffff9c, &(0x7f0000000040), 0x121403, 0x0) ioctl$FS_IOC_SETFLAGS(r4, 0x40081271, &(0x7f0000000980)=0x4000) mount(&(0x7f0000000140)=@nullb, &(0x7f0000000040)='./cgroup\x00', &(0x7f0000000000)='ntfs3\x00', 0x2208004, 0x0) syz_clone(0x88200200, 0x0, 0x0, 0x0, 0x0, 0x0) Here, the ioctl sets the bdev block size to 16384. During mount, get_tree_bdev_flags() calls sb_set_blocksize(sb, block_size(bdev)), but since block_size(bdev) > PAGE_SIZE, sb_set_blocksize() leaves sb->s_blocksize at zero. Later, ntfs_init_from_boot() attempts to read the boot_block while sb->s_blocksize is still zero, which triggers the bug. [almaz.alexandrovich@paragon-software.com: changed comment style, added return value handling]
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/44a38eb4f7876513db5a1bccde74de9bc4389d43
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4fff9a625da958a33191c8553a03283786f9f417
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b3c151fe8f543f1a0b8b5df16ce5d97afa5ec85a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d1693a7d5a38acf6424235a6070bcf5b186a360d
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nntfs: set dummy blocksize to read boot_block when mounting\n\nWhen mounting, sb-\u003es_blocksize is used to read the boot_block without\nbeing defined or validated. Set a dummy blocksize before attempting to\nread the boot_block.\n\nThe issue can be triggered with the following syz reproducer:\n\n  mkdirat(0xffffffffffffff9c, \u0026(0x7f0000000080)=\u0027./file1\\x00\u0027, 0x0)\n  r4 = openat$nullb(0xffffffffffffff9c, \u0026(0x7f0000000040), 0x121403, 0x0)\n  ioctl$FS_IOC_SETFLAGS(r4, 0x40081271, \u0026(0x7f0000000980)=0x4000)\n  mount(\u0026(0x7f0000000140)=@nullb, \u0026(0x7f0000000040)=\u0027./cgroup\\x00\u0027,\n        \u0026(0x7f0000000000)=\u0027ntfs3\\x00\u0027, 0x2208004, 0x0)\n  syz_clone(0x88200200, 0x0, 0x0, 0x0, 0x0, 0x0)\n\nHere, the ioctl sets the bdev block size to 16384. During mount,\nget_tree_bdev_flags() calls sb_set_blocksize(sb, block_size(bdev)),\nbut since block_size(bdev) \u003e PAGE_SIZE, sb_set_blocksize() leaves\nsb-\u003es_blocksize at zero.\n\nLater, ntfs_init_from_boot() attempts to read the boot_block while\nsb-\u003es_blocksize is still zero, which triggers the bug.\n\n[almaz.alexandrovich@paragon-software.com: changed comment style, added\nreturn value handling]"
    }
  ],
  "id": "CVE-2025-71067",
  "lastModified": "2026-01-14T16:26:00.933",
  "metrics": {},
  "published": "2026-01-13T16:16:06.077",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/44a38eb4f7876513db5a1bccde74de9bc4389d43"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/4fff9a625da958a33191c8553a03283786f9f417"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b3c151fe8f543f1a0b8b5df16ce5d97afa5ec85a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d1693a7d5a38acf6424235a6070bcf5b186a360d"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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