CVE-2026-90133 (GCVE-0-2026-90133)
Vulnerability from cvelistv5
Published
2026-09-17 16:06
Modified
2026-10-19 08:58
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
ntfs: Fix index_root heap OOB write in ntfs_ir_to_ib()
ntfs_ir_to_ib copies all entries from index_root into a freshly allocated
index_block_size-byte buffer without verifying that the entries fit in the
available space. The entries in index_root may be larger than the usable
entry space in the index block.
This can cause OOB writes past the end of the allocation.
The validator ntfs_index_root_inconsistent() checks that entries are
self-consistent within the IR value, but never cross-checks them against
index_block_size. There is no bounds check in ntfs_ir_to_ib() before the
memcpy.
Fixing this at the sink in ntfs_ir_to_ib() since
ntfs_index_root_inconsistent() validates the logical consistency of
index_root as a structure and a root with large entries is a structurally
valid root. The bug is a size conflict of ntfs_ir_to_ib().
Also, the validator is called once per inode load in
ntfs_read_locked_inode() while ntfs_ir_to_ib() is only called during a
reparent, a check there adds no overhead to the common path.
Moreover, even a future call path that bypasses the validator would still
be protected.
With NULL as first parameter of ntfs_error(), the volume error flag is
never set by this call, so the device name will be absent from the error
message. In any case, that the caller, ntfs_ir_reparent(), prints an error
message that includes the device name on NULL returns.
I think this is the best solution available without adding
'struct super_block *sb' as a parameter to ntfs_ir_to_ib().
This heap out-of-bounds write is triggered by a crafted filesystem image,
which is not in the kernel threat model, anyway, fixing memory errors would
be nice to keep things secure.
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"fs/ntfs/index.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "825dec5120933e90c54e30e31ccfa6c3449043a8",
"status": "affected",
"version": "0a8ac0c1fa0b99a5b29002bc7f232ed7eafddef0",
"versionType": "git"
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{
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"status": "affected",
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]
},
{
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"product": "Linux",
"programFiles": [
"fs/ntfs/index.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "7.1"
},
{
"lessThan": "7.1",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.6",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2.6",
"versionStartIncluding": "7.1",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.3",
"versionStartIncluding": "7.1",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
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],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nntfs: Fix index_root heap OOB write in ntfs_ir_to_ib()\n\nntfs_ir_to_ib copies all entries from index_root into a freshly allocated\nindex_block_size-byte buffer without verifying that the entries fit in the\navailable space. The entries in index_root may be larger than the usable\nentry space in the index block.\n\nThis can cause OOB writes past the end of the allocation.\n\nThe validator ntfs_index_root_inconsistent() checks that entries are\nself-consistent within the IR value, but never cross-checks them against\nindex_block_size. There is no bounds check in ntfs_ir_to_ib() before the\nmemcpy.\n\nFixing this at the sink in ntfs_ir_to_ib() since\nntfs_index_root_inconsistent() validates the logical consistency of\nindex_root as a structure and a root with large entries is a structurally\nvalid root. The bug is a size conflict of ntfs_ir_to_ib().\nAlso, the validator is called once per inode load in\nntfs_read_locked_inode() while ntfs_ir_to_ib() is only called during a\nreparent, a check there adds no overhead to the common path.\nMoreover, even a future call path that bypasses the validator would still\nbe protected.\n\nWith NULL as first parameter of ntfs_error(), the volume error flag is\nnever set by this call, so the device name will be absent from the error\nmessage. In any case, that the caller, ntfs_ir_reparent(), prints an error\nmessage that includes the device name on NULL returns.\nI think this is the best solution available without adding\n\u0027struct super_block *sb\u0027 as a parameter to ntfs_ir_to_ib().\n\nThis heap out-of-bounds write is triggered by a crafted filesystem image,\nwhich is not in the kernel threat model, anyway, fixing memory errors would\nbe nice to keep things secure."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - The overflow source is on-disk $INDEX_ROOT (ir-\u003eindex_block_size and the resident entries) that ntfs_ir_to_ib() memcpy()s; the trigger is vfs_create/mkdir/link/rename \u2192 ntfs_create/__ntfs_link \u2192 ntfs_index_add_filename \u2192 ntfs_ie_add \u2192 ntfs_ir_make_space \u2192 ntfs_ir_reparent. No protocol message carries those fields.\nAC:L - ntfs_read_locked_inode() accepts any power-of-two index_block_size in [512, PAGE_SIZE] and ntfs_index_root_inconsistent() never compares entry bytes to that size, so a 512-byte IB plus a packed resident INDEX_ROOT in a full MFT record makes ntfs_ir_truncate() return -ENOSPC and ntfs_ir_reparent() run on the next create, with no race.\nPR:N - mount_capable() needs init-namespace CAP_SYS_ADMIN because ntfs_fs_type lacks FS_USERNS_MOUNT; that mount is the victim or udisks2/vold action (UI:R), not attacker privilege. After mount, ntfs_create() is an ordinary VFS create on a directory whose mode the image controls, so the attacker needs no account.\nUI:R - ntfs_ir_to_ib() is called only from ntfs_ir_reparent(), not from ntfs_fill_super(), so attaching the volume is not enough. A victim or automounter must mount the attacker-supplied NTFS image, and then create/mkdir/link/rename must add a filename so ntfs_ie_add() takes the ENOSPC reparent path.\nS:U - The kvzalloc(index_block) overflow in ntfs_ir_to_ib() corrupts host-kernel heap in the same OS authority as fs/ntfs; it is in-kernel memory corruption, not a VM escape, IOMMU bypass, or sandbox breakout.\nC:H - memcpy() in ntfs_ir_to_ib() writes attacker-controlled INDEX_ROOT entry bytes (UTF-16 names, MFT refs) past the kvzalloc(ir-\u003eindex_block_size) object into adjacent slab, a heap OOB write that can be groomed to disclose neighboring kernel objects.\nI:H - The same memcpy is an unbounded heap out-of-bounds write of attacker-chosen index-entry contents past the allocated index_block, which can corrupt adjacent slab objects and hijack kernel control flow.\nA:H - Writing past the kvzalloc index_block into unmapped or poisoned adjacent heap oopses or panics on the ntfs_ir_reparent() create/mkdir path, fully denying availability even when the overflow is not turned into a write primitive."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-10-19T08:58:31.458Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/825dec5120933e90c54e30e31ccfa6c3449043a8"
},
{
"url": "https://git.kernel.org/stable/c/dc09bf79b76f9a7157e225f449655f3f62f96c9c"
}
],
"title": "ntfs: Fix index_root heap OOB write in ntfs_ir_to_ib()",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-90133",
"datePublished": "2026-09-17T16:06:33.234Z",
"dateReserved": "2026-09-11T19:38:34.788Z",
"dateUpdated": "2026-10-19T08:58:31.458Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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