Description
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.
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.
Published:
2026-10-28
Score:
n/a
EPSS:
n/a
KEV:
No
Impact:
n/a
Action:
n/a
Analysis
No analysis available yet.
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 remediation available yet.
Tracking
Sign in to view the affected projects.
Advisories
No advisories yet.
References
History
Wed, 28 Oct 2026 10:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | ntfs3: free the sbi after a grace period | |
| 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: 2026-10-28T10:35:26.598Z
Reserved: 2026-09-25T10:25:14.399Z
Link: CVE-2026-99171
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-10-28T11:17:37.660
Modified: 2026-10-28T11:17:37.660
Link: CVE-2026-99171
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.