Description
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---
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---
Published:
2026-08-15
Score:
n/a
EPSS:
< 1% Very Low
KEV:
No
Impact:
n/a
Action:
n/a
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
|||||||||||||||
| Linux | Linux | affected |
|
No data.
No data.
No data available yet.
Remediation
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
Sign in to view the affected projects.
Advisories
No advisories yet.
References
History
Sat, 15 Aug 2026 11:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-416 |
Sat, 15 Aug 2026 06:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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--- | |
| Title | ntfs: avoid stale runlist element dereference in MFT writeback | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-08-15T05:55:56.163Z
Reserved: 2026-08-09T03:40:39.921Z
Link: CVE-2026-72354
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-08-15T06:22:08.840
Modified: 2026-08-15T06:22:08.840
Link: CVE-2026-72354
Redhat
No data.
OpenCVE Enrichment
Updated: 2026-08-15T11:00:05Z
Weaknesses
-
CWE-416
Use After Free