CVE-2026-99171 (GCVE-0-2026-99171)
Vulnerability from cvelistv5
Published
2026-10-28 10:35
Modified
2026-10-28 10:35
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
ntfs3: free the sbi after a grace period
If the "nocase" mount option ntfs3 uses custom hash and dentry compare
functions. Both access ntfs3 superblock private information in rcu
pathwalk. ntfs_put_super() and ntfs3_kill_sb() drop the info without any
rcu delay. A lookup that's still inside the filesystem when the last
reference to the mount is dropped causes a UAF. With a pathwalk held up
in ntfs_d_hash() while the last reference to the mount goes away:
BUG: KASAN: slab-use-after-free in ntfs_nls_to_utf16+0x752/0x940
Read of size 8 at addr ff1100010453c850 by task walker/99
Call Trace:
<TASK>
ntfs_nls_to_utf16+0x752/0x940
ntfs_d_hash+0x22b/0x500
link_path_walk+0x11ad/0x1d30
path_lookupat+0x63/0xb00
filename_lookup+0x1f1/0x5b0
vfs_statx+0xd7/0x3b0
[...]
Allocated by task 95:
__kmalloc_cache_noprof+0x249/0x560
ntfs_init_fs_context+0x2db/0x5a0
alloc_fs_context+0x52e/0xc70
[...]
Freed by task 98:
kfree+0x1db/0x5b0
deactivate_locked_super+0x9c/0xf0
cleanup_mnt+0x9f/0x130
task_work_run+0x131/0x250
The bug is currently masked by the grace period in namespace_unlock()
for umount(2). Keep the necessary information until the filesystem
private info is freed and free it with an rcu delay.
ntfs3_free_sbi() now runs from an rcu callback and drops the upcase
table via ntfs_put_shared(). So switch s_shared_lock over to
spin_lock_bh(). Otherwise the callback can deadlock against a task
holding the lock on the same cpu.
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"fs/ntfs3/ntfs_fs.h",
"fs/ntfs3/super.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "c8b1a4840467930e01f1a9374d991d7a8a2896c1",
"status": "affected",
"version": "a3a956c78efaa202b1d75190136671cf6e87bfbe",
"versionType": "git"
},
{
"lessThan": "7abecef26a9be8f9de70659a3092250461a52072",
"status": "affected",
"version": "a3a956c78efaa202b1d75190136671cf6e87bfbe",
"versionType": "git"
},
{
"lessThan": "c01b091b06412d3b1b53d8c2925f6de586c8a2fc",
"status": "affected",
"version": "a3a956c78efaa202b1d75190136671cf6e87bfbe",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"fs/ntfs3/ntfs_fs.h",
"fs/ntfs3/super.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.2"
},
{
"lessThan": "6.2",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.59",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.13",
"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": "6.18.59",
"versionStartIncluding": "6.2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2.13",
"versionStartIncluding": "6.2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.3",
"versionStartIncluding": "6.2",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nntfs3: free the sbi after a grace period\n\nIf the \"nocase\" mount option ntfs3 uses custom hash and dentry compare\nfunctions. Both access ntfs3 superblock private information in rcu\npathwalk. ntfs_put_super() and ntfs3_kill_sb() drop the info without any\nrcu delay. A lookup that\u0027s still inside the filesystem when the last\nreference to the mount is dropped causes a UAF. With a pathwalk held up\nin ntfs_d_hash() while the last reference to the mount goes away:\n\n BUG: KASAN: slab-use-after-free in ntfs_nls_to_utf16+0x752/0x940\n Read of size 8 at addr ff1100010453c850 by task walker/99\n Call Trace:\n \u003cTASK\u003e\n ntfs_nls_to_utf16+0x752/0x940\n ntfs_d_hash+0x22b/0x500\n link_path_walk+0x11ad/0x1d30\n path_lookupat+0x63/0xb00\n filename_lookup+0x1f1/0x5b0\n vfs_statx+0xd7/0x3b0\n [...]\n Allocated by task 95:\n __kmalloc_cache_noprof+0x249/0x560\n ntfs_init_fs_context+0x2db/0x5a0\n alloc_fs_context+0x52e/0xc70\n [...]\n Freed by task 98:\n kfree+0x1db/0x5b0\n deactivate_locked_super+0x9c/0xf0\n cleanup_mnt+0x9f/0x130\n task_work_run+0x131/0x250\n\nThe bug is currently masked by the grace period in namespace_unlock()\nfor umount(2). Keep the necessary information until the filesystem\nprivate info is freed and free it with an rcu delay.\n\nntfs3_free_sbi() now runs from an rcu callback and drops the upcase\ntable via ntfs_put_shared(). So switch s_shared_lock over to\nspin_lock_bh(). Otherwise the callback can deadlock against a task\nholding the lock on the same cpu."
}
],
"providerMetadata": {
"dateUpdated": "2026-10-28T10:35:26.598Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/c8b1a4840467930e01f1a9374d991d7a8a2896c1"
},
{
"url": "https://git.kernel.org/stable/c/7abecef26a9be8f9de70659a3092250461a52072"
},
{
"url": "https://git.kernel.org/stable/c/c01b091b06412d3b1b53d8c2925f6de586c8a2fc"
}
],
"title": "ntfs3: free the sbi after a grace period",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-99171",
"datePublished": "2026-10-28T10:35:26.598Z",
"dateReserved": "2026-09-25T10:25:14.399Z",
"dateUpdated": "2026-10-28T10:35:26.598Z",
"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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