FKIE_CVE-2025-71067
Vulnerability from fkie_nvd - Published: 2026-01-13 16:16 - Updated: 2026-04-15 00:35
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
Impacted products
| Vendor | Product | Version |
|---|
{
"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]"
},
{
"lang": "es",
"value": "En el n\u00facleo de Linux, se ha solucionado la siguiente vulnerabilidad: ntfs: se establece un tama\u00f1o de bloque ficticio para leer boot_block al montar. Al montar, se utiliza sb-\u0026gt;s_blocksize para leer boot_block sin que est\u00e9 definido ni validado. Establecer un tama\u00f1o de bloque ficticio antes de intentar leer el boot_block. El problema se puede reproducir con el siguiente c\u00f3digo de Syz: mkdirat(0xffffffffffffff9c, \u0026amp;(0x7f0000000080)=\u201c./file1\\x00\u201d, 0x0) r4 = openat$nullb(0xffffffffffffff9c, \u0026amp;(0x7f0000000040), 0x121403, 0x0) ioctl$FS_IOC_SETFLAGS(r4, 0x40081271, \u0026amp;(0x7f0000000980)=0x4000) mount(\u0026amp;(0x7f0000000140)=@nullb, \u0026amp;(0x7f0000000040)=\u0027./ cgroup\\x00\u0027, \u0026amp;(0x7f0000000000)=\u201cntfs3\\x00\u201d, 0x2208004, 0x0) syz_clone(0x88200200, 0x0, 0x0, 0x0, 0x0, 0x0) Aqu\u00ed, el ioctl establece el tama\u00f1o de bloque de bdev en 16384. Durante el montaje, get_tree_bdev_flags() llama a sb_set_blocksize(sb, block_size(bdev)), pero dado que block_size(bdev) \u0026gt; PAGE_SIZE, sb_set_blocksize() deja sb-\u0026gt;s_blocksize en cero. M\u00e1s tarde, ntfs_init_from_boot() intenta leer el boot_block mientras sb-\u0026gt;s_blocksize sigue siendo cero, lo que desencadena el error. [almaz.alexandrovich@paragon-software.com: se ha cambiado el estilo de los comentarios y se ha a\u00f1adido el manejo del valor de retorno]"
}
],
"id": "CVE-2025-71067",
"lastModified": "2026-04-15T00:35:42.020",
"metrics": {},
"published": "2026-01-13T16:16:06.077",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/0c9327c8abf9c8f046e45008bb43d94d8ee5c6c5"
},
{
"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": "Deferred"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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