FKIE_CVE-2026-72354
Vulnerability from fkie_nvd - Published: 2026-08-15 06:22 - Updated: 2026-08-17 06:18
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
ntfs: avoid stale runlist element dereference in MFT writeback
ntfs_write_mft_block() maps each $MFT record through the $MFT data
runlist. For sub-folio clusters it looks up a struct runlist_element under
ni->runlist.lock, drops the lock, and later uses rl->length and rl->vcn
when choosing folio_sz.
That pointer is only borrowed from ni->runlist.rl. Concurrent $MFT
allocation extension can merge a replacement runlist under the same lock,
and ntfs_rl_realloc() can free the old backing array. If that happens
between the lookup and the later folio_sz decision, writeback can
dereference freed runlist storage.
The buggy scenario involves two paths, with each column showing the order
within that path:
MFT writeback path: $MFT allocation extension:
1. Look up rl under 1. Extend the $MFT data allocation.
ni->runlist.lock. 2. Publish a replacement runlist.
2. Drop ni->runlist.lock. 3. Free the old runlist array.
3. Read rl->length and rl->vcn
to choose folio_sz.
Compute the remaining run length while ni->runlist.lock is still held, and
use that scalar after unlock. This preserves the existing folio sizing
decision without carrying a borrowed runlist_element across the lock
boundary.
Validation reproduced this kernel report:
BUG: KASAN: slab-use-after-free in ntfs_mft_writepages+0x1c8d/0x1fb0
Call Trace:
<TASK>
dump_stack_lvl+0x66/0xa0
print_report+0xce/0x630
? ntfs_mft_writepages+0x1c8d/0x1fb0
? srso_alias_return_thunk+0x5/0xfbef5
? __virt_addr_valid+0x20d/0x410
? ntfs_mft_writepages+0x1c8d/0x1fb0
kasan_report+0xe0/0x110
? ntfs_mft_writepages+0x1c8d/0x1fb0
ntfs_mft_writepages+0x1c8d/0x1fb0
? __pfx_ntfs_mft_writepages+0x10/0x10
? __pfx___mutex_unlock_slowpath+0x10/0x10
? srso_alias_return_thunk+0x5/0xfbef5
? iput+0x92/0xa80
do_writepages+0x219/0x530
? __pfx_do_writepages+0x10/0x10
__writeback_single_inode+0x117/0xf50
? do_raw_spin_lock+0x130/0x270
? __pfx_do_raw_spin_lock+0x10/0x10
? __pfx___writeback_single_inode+0x10/0x10
? srso_alias_return_thunk+0x5/0xfbef5
writeback_sb_inodes+0x65b/0x1810
? srso_alias_return_thunk+0x5/0xfbef5
? lock_acquire+0x2b8/0x2f0
? __pfx_writeback_sb_inodes+0x10/0x10
? lock_release+0x1e0/0x280
? _raw_spin_unlock+0x23/0x40
? move_expired_inodes+0x2b8/0x850
__writeback_inodes_wb+0xf4/0x270
? __pfx___writeback_inodes_wb+0x10/0x10
? srso_alias_return_thunk+0x5/0xfbef5
? queue_io+0x2e4/0x410
wb_writeback+0x666/0x880
? srso_alias_return_thunk+0x5/0xfbef5
? __pfx_wb_writeback+0x10/0x10
? srso_alias_return_thunk+0x5/0xfbef5
? srso_alias_return_thunk+0x5/0xfbef5
? get_nr_dirty_inodes+0x1c/0x170
wb_workfn+0x75e/0xbb0
? srso_alias_return_thunk+0x5/0xfbef5
? _raw_spin_unlock_irqrestore+0x27/0x60
? __pfx_wb_workfn+0x10/0x10
? __pfx_debug_object_deactivate+0x10/0x10
? lock_acquire+0x2b8/0x2f0
? srso_alias_return_thunk+0x5/0xfbef5
? lock_release+0x1e0/0x280
process_one_work+0x8d0/0x1870
? __pfx_process_one_work+0x10/0x10
? srso_alias_return_thunk+0x5/0xfbef5
worker_thread+0x575/0xf80
? __pfx_worker_thread+0x10/0x10
kthread+0x2e7/0x3c0
? __pfx_kthread+0x10/0x10
ret_from_fork+0x576/0x810
? __pfx_ret_from_fork+0x10/0x10
? srso_alias_return_thunk+0x5/0xfbef5
? __switch_to+0x57e/0xe10
? __switch_to_asm+0x33/0x70
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 970:
kasan_save_stack+0x33/0x60
kasan_save_track+0x14/0x30
__kasan_kmalloc+0xaa/0xb0
__kvmalloc_node_noprof+0x353/0x920
ntfs_rl_realloc+0x3c/0x80
ntfs_runlists_merge+0x1212/0x3010
ntfs_mft_data_extend_allocation_nolock+0x3e0/0x1f40
ntfs_mft_record_alloc+0x1ab4/0x4f10
__ntfs_create+0x680/0x2e50
ntfs_create+0x1e6/0x3a0
path_openat+0x2b55/0x3c10
do_file_open+0x1f4/0x460
do_sys_openat2+0xde/0x170
__x64_sys_openat+0x122/0x1e0
do_syscall_64+0x115/0x6a0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 1294:
kasan_save_
---truncated---
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"fs/ntfs/mft.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "9a2e36963a3fc52401586657d34e3f1c5a01ea56",
"status": "affected",
"version": "115380f9a2f9675c7924563cbba70d40cae8fb81",
"versionType": "git"
},
{
"lessThan": "81fe702ff1760da32bcd3ef4494b2a33dbeced72",
"status": "affected",
"version": "115380f9a2f9675c7924563cbba70d40cae8fb81",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"fs/ntfs/mft.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": "7.1.*",
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nntfs: avoid stale runlist element dereference in MFT writeback\n\nntfs_write_mft_block() maps each $MFT record through the $MFT data\nrunlist. For sub-folio clusters it looks up a struct runlist_element under\nni-\u003erunlist.lock, drops the lock, and later uses rl-\u003elength and rl-\u003evcn\nwhen choosing folio_sz.\n\nThat pointer is only borrowed from ni-\u003erunlist.rl. Concurrent $MFT\nallocation extension can merge a replacement runlist under the same lock,\nand ntfs_rl_realloc() can free the old backing array. If that happens\nbetween the lookup and the later folio_sz decision, writeback can\ndereference freed runlist storage.\n\nThe buggy scenario involves two paths, with each column showing the order\nwithin that path:\n\nMFT writeback path: $MFT allocation extension:\n1. Look up rl under 1. Extend the $MFT data allocation.\n ni-\u003erunlist.lock. 2. Publish a replacement runlist.\n2. Drop ni-\u003erunlist.lock. 3. Free the old runlist array.\n3. Read rl-\u003elength and rl-\u003evcn\n to choose folio_sz.\n\nCompute the remaining run length while ni-\u003erunlist.lock is still held, and\nuse that scalar after unlock. This preserves the existing folio sizing\ndecision without carrying a borrowed runlist_element across the lock\nboundary.\n\nValidation reproduced this kernel report:\nBUG: KASAN: slab-use-after-free in ntfs_mft_writepages+0x1c8d/0x1fb0\n\nCall Trace:\n \u003cTASK\u003e\n dump_stack_lvl+0x66/0xa0\n print_report+0xce/0x630\n ? ntfs_mft_writepages+0x1c8d/0x1fb0\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? __virt_addr_valid+0x20d/0x410\n ? ntfs_mft_writepages+0x1c8d/0x1fb0\n kasan_report+0xe0/0x110\n ? ntfs_mft_writepages+0x1c8d/0x1fb0\n ntfs_mft_writepages+0x1c8d/0x1fb0\n ? __pfx_ntfs_mft_writepages+0x10/0x10\n ? __pfx___mutex_unlock_slowpath+0x10/0x10\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? iput+0x92/0xa80\n do_writepages+0x219/0x530\n ? __pfx_do_writepages+0x10/0x10\n __writeback_single_inode+0x117/0xf50\n ? do_raw_spin_lock+0x130/0x270\n ? __pfx_do_raw_spin_lock+0x10/0x10\n ? __pfx___writeback_single_inode+0x10/0x10\n ? srso_alias_return_thunk+0x5/0xfbef5\n writeback_sb_inodes+0x65b/0x1810\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? lock_acquire+0x2b8/0x2f0\n ? __pfx_writeback_sb_inodes+0x10/0x10\n ? lock_release+0x1e0/0x280\n ? _raw_spin_unlock+0x23/0x40\n ? move_expired_inodes+0x2b8/0x850\n __writeback_inodes_wb+0xf4/0x270\n ? __pfx___writeback_inodes_wb+0x10/0x10\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? queue_io+0x2e4/0x410\n wb_writeback+0x666/0x880\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? __pfx_wb_writeback+0x10/0x10\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? get_nr_dirty_inodes+0x1c/0x170\n wb_workfn+0x75e/0xbb0\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? _raw_spin_unlock_irqrestore+0x27/0x60\n ? __pfx_wb_workfn+0x10/0x10\n ? __pfx_debug_object_deactivate+0x10/0x10\n ? lock_acquire+0x2b8/0x2f0\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? lock_release+0x1e0/0x280\n process_one_work+0x8d0/0x1870\n ? __pfx_process_one_work+0x10/0x10\n ? srso_alias_return_thunk+0x5/0xfbef5\n worker_thread+0x575/0xf80\n ? __pfx_worker_thread+0x10/0x10\n kthread+0x2e7/0x3c0\n ? __pfx_kthread+0x10/0x10\n ret_from_fork+0x576/0x810\n ? __pfx_ret_from_fork+0x10/0x10\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? __switch_to+0x57e/0xe10\n ? __switch_to_asm+0x33/0x70\n ? __pfx_kthread+0x10/0x10\n ret_from_fork_asm+0x1a/0x30\n \u003c/TASK\u003e\n\nAllocated by task 970:\n kasan_save_stack+0x33/0x60\n kasan_save_track+0x14/0x30\n __kasan_kmalloc+0xaa/0xb0\n __kvmalloc_node_noprof+0x353/0x920\n ntfs_rl_realloc+0x3c/0x80\n ntfs_runlists_merge+0x1212/0x3010\n ntfs_mft_data_extend_allocation_nolock+0x3e0/0x1f40\n ntfs_mft_record_alloc+0x1ab4/0x4f10\n __ntfs_create+0x680/0x2e50\n ntfs_create+0x1e6/0x3a0\n path_openat+0x2b55/0x3c10\n do_file_open+0x1f4/0x460\n do_sys_openat2+0xde/0x170\n __x64_sys_openat+0x122/0x1e0\n do_syscall_64+0x115/0x6a0\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nFreed by task 1294:\n kasan_save_\n---truncated---"
}
],
"id": "CVE-2026-72354",
"lastModified": "2026-08-17T06:18:39.540",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 8.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 2.8,
"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-08-15T06:22:08.840",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/81fe702ff1760da32bcd3ef4494b2a33dbeced72"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/9a2e36963a3fc52401586657d34e3f1c5a01ea56"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
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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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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