CVE-2026-97438fs/ntfs3: validate index entry key bounds

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.

CVSS

7.1 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H

Weakness (CWE)

Not given

Known exploited

Not in CISA's KEV catalog

EPSS (exploitation in the next 30 days)

Not loaded for this CVE

Assigned by

Linux

NVD analysis

Received

Record last updated

Oct 3, 2026

First seen by InfoSec Signals

Oct 9, 2026

The CVE record on cve.org · NVD's entry

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