---
id: CVE-2026-97438
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  fs/ntfs3: validate index entry key bounds

  [BUG]
  A malformed NTFS directory index entry can advertise a key_size larger
  than the bytes actually present in its NTFS_DE p…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  fs/ntfs3: validate index entry key bounds

  [BUG]
  A malformed NTFS directory index entry can advertise a key_size larger
  than the bytes actually present in its NTFS_DE p…
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H'
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    a8f4fb6a7d58974ffc9aed597401528b181d76dc
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    0257e3ea00e19129f3ad5c039d8b8fdff0796835
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    98d6e5d9dc1d34dcffc61549617581a5fe1ef807
  - Linux < 6.12.111
  - Linux < 6.18.53
  - Linux (all versions)
published: '2026-09-24'
updated: '2026-09-25'
sourceUpdated: '2026-09-25T13:17:27.430'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-97438'
references:
  - url: 'https://git.kernel.org/stable/c/0257e3ea00e19129f3ad5c039d8b8fdff0796835'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/98d6e5d9dc1d34dcffc61549617581a5fe1ef807'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a8f4fb6a7d58974ffc9aed597401528b181d76dc'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-24T16:47:15.879Z'
epss: 0.0013
epssPercentile: 0.02145
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

fs/ntfs3: validate index entry key bounds

[BUG]
A malformed NTFS directory index entry can advertise a key_size larger
than the bytes actually present in its NTFS_DE payload. Directory lookup
then passes that malformed key to cmp_fnames(), which can read past the
end of the kmalloc'ed index buffer.

BUG: KASAN: slab-out-of-bounds in fname_full_size fs/ntfs3/ntfs.h:590 [inline]
BUG: KASAN: slab-out-of-bounds in cmp_fnames+0x1ea/0x230 fs/ntfs3/index.c:46
Read of size 1 at addr ffff88801c313018 by task syz.6.3365/9279

Call Trace:
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0xbe/0x130 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xd1/0x650 mm/kasan/report.c:482
 kasan_report+0xfb/0x140 mm/kasan/report.c:595
 __asan_report_load1_noabort+0x14/0x30 mm/kasan/report_generic.c:378
 fname_full_size fs/ntfs3/ntfs.h:590 [inline]
 cmp_fnames+0x1ea/0x230 fs/ntfs3/index.c:46
 hdr_find_e.isra.0+0x3ed/0x670 fs/ntfs3/index.c:762
 indx_find+0x4b5/0x900 fs/ntfs3/index.c:1186
 dir_search_u+0x2c0/0x460 fs/ntfs3/dir.c:254
 ntfs_lookup+0x1cc/0x2a0 fs/ntfs3/namei.c:85
 __lookup_slow+0x241/0x450 fs/namei.c:1816
 lookup_slow fs/namei.c:1833 [inline]
 walk_component+0x31c/0x570 fs/namei.c:2151
 link_path_walk+0x592/0xd60 fs/namei.c:2519
 path_lookupat+0x138/0x660 fs/namei.c:2675
 filename_lookup+0x1f3/0x560 fs/namei.c:2705
 filename_setxattr+0xad/0x1c0 fs/xattr.c:660
 path_setxattrat+0x1d8/0x280 fs/xattr.c:713
 __do_sys_lsetxattr fs/xattr.c:754 [inline]
 __se_sys_lsetxattr fs/xattr.c:750 [inline]
 __x64_sys_lsetxattr+0xd0/0x150 fs/xattr.c:750
 ...

Allocated by task 9279:
 kasan_save_stack+0x39/0x70 mm/kasan/common.c:56
 kasan_save_track+0x14/0x40 mm/kasan/common.c:77
 kasan_save_alloc_info+0x37/0x60 mm/kasan/generic.c:573
 poison_kmalloc_redzone mm/kasan/common.c:400 [inline]
 __kasan_kmalloc+0xc3/0xd0 mm/kasan/common.c:417
 kasan_kmalloc include/linux/kasan.h:262 [inline]
 __do_kmalloc_node mm/slub.c:5650 [inline]
 __kmalloc_noprof+0x2bd/0x900 mm/slub.c:5662
 kmalloc_noprof include/linux/slab.h:961 [inline]
 indx_read+0x41d/0xad0 fs/ntfs3/index.c:1059
 indx_find+0x447/0x900 fs/ntfs3/index.c:1179
 dir_search_u+0x2c0/0x460 fs/ntfs3/dir.c:254
 ntfs_lookup+0x1cc/0x2a0 fs/ntfs3/namei.c:85
 __lookup_slow+0x241/0x450 fs/namei.c:1816
 lookup_slow fs/namei.c:1833 [inline]
 walk_component+0x31c/0x570 fs/namei.c:2151
 link_path_walk+0x592/0xd60 fs/namei.c:2519
 path_lookupat+0x138/0x660 fs/namei.c:2675
 filename_lookup+0x1f3/0x560 fs/namei.c:2705
 filename_setxattr+0xad/0x1c0 fs/xattr.c:660
 path_setxattrat+0x1d8/0x280 fs/xattr.c:713
 __do_sys_lsetxattr fs/xattr.c:754 [inline]
 __se_sys_lsetxattr fs/xattr.c:750 [inline]
 __x64_sys_lsetxattr+0xd0/0x150 fs/xattr.c:750
 ...

[CAUSE]
The index-header validators only validated INDEX_HDR-level geometry.
They did not walk each NTFS_DE to verify entry alignment, subnode
layout, or that key_size fit inside the entry payload. They also
allowed a last sentinel entry to carry a non-zero key_size.

[FIX]
Walk every NTFS_DE in ntfs3's index-header validators and reject
entries with invalid layout, mismatched subnode state, oversized
key_size, or non-zero sentinel keys before lookup or log replay can
consume them.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.