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

ntfs: fix use-after-free in ntfs_attr_find()

Patch series "ntfs: fix bugs about Attribute", v2.

This patchset fixes three bugs relative to Attribute in record:

Patch 1 adds a sanity check to ensure that, attrs_offset field in first
mft record loading from disk is within bounds.

Patch 2 moves the ATTR_RECORD's bounds checking earlier, to avoid
dereferencing ATTR_RECORD before checking this ATTR_RECORD is within
bounds.

Patch 3 adds an overflow checking to avoid possible forever loop in
ntfs_attr_find().

Without patch 1 and patch 2, the kernel triggersa KASAN use-after-free
detection as reported by Syzkaller.

Although one of patch 1 or patch 2 can fix this, we still need both of
them. Because patch 1 fixes the root cause, and patch 2 not only fixes
the direct cause, but also fixes the potential out-of-bounds bug.


This patch (of 3):

Syzkaller reported use-after-free read as follows:
==================================================================
BUG: KASAN: use-after-free in ntfs_attr_find+0xc02/0xce0 fs/ntfs/attrib.c:597
Read of size 2 at addr ffff88807e352009 by task syz-executor153/3607

[...]
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:317 [inline]
print_report.cold+0x2ba/0x719 mm/kasan/report.c:433
kasan_report+0xb1/0x1e0 mm/kasan/report.c:495
ntfs_attr_find+0xc02/0xce0 fs/ntfs/attrib.c:597
ntfs_attr_lookup+0x1056/0x2070 fs/ntfs/attrib.c:1193
ntfs_read_inode_mount+0x89a/0x2580 fs/ntfs/inode.c:1845
ntfs_fill_super+0x1799/0x9320 fs/ntfs/super.c:2854
mount_bdev+0x34d/0x410 fs/super.c:1400
legacy_get_tree+0x105/0x220 fs/fs_context.c:610
vfs_get_tree+0x89/0x2f0 fs/super.c:1530
do_new_mount fs/namespace.c:3040 [inline]
path_mount+0x1326/0x1e20 fs/namespace.c:3370
do_mount fs/namespace.c:3383 [inline]
__do_sys_mount fs/namespace.c:3591 [inline]
__se_sys_mount fs/namespace.c:3568 [inline]
__x64_sys_mount+0x27f/0x300 fs/namespace.c:3568
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
[...]
</TASK>

The buggy address belongs to the physical page:
page:ffffea0001f8d400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7e350
head:ffffea0001f8d400 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888011842140
raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88807e351f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88807e351f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88807e352000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88807e352080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88807e352100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Kernel will loads $MFT/$DATA's first mft record in
ntfs_read_inode_mount().

Yet the problem is that after loading, kernel doesn't check whether
attrs_offset field is a valid value.

To be more specific, if attrs_offset field is larger than bytes_allocated
field, then it may trigger the out-of-bounds read bug(reported as
use-after-free bug) in ntfs_attr_find(), when kernel tries to access the
corresponding mft record's attribute.

This patch solves it by adding the sanity check between attrs_offset field
and bytes_allocated field, after loading the first mft record.

Metrics

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00123.

Key SSVC decision points have not yet been added.

Affected Vendors & Products

No data.

No data.

No data.

No data.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://git.kernel.org/stable/c/266bd5306286316758e6246ea0345133427b0f62 cve-icon cve-icon
https://git.kernel.org/stable/c/4863f815463034f588a035cfd99cdca97a4f1069 cve-icon cve-icon
https://git.kernel.org/stable/c/5330c423b86263ac7883fef0260b9e2229cb531e cve-icon cve-icon
https://git.kernel.org/stable/c/79f3ac7dcd12c05b7539239a4c6fa229a50d786c cve-icon cve-icon
https://git.kernel.org/stable/c/b825bfbbaafbe8da2037e3a778ad660c59f9e054 cve-icon cve-icon
https://git.kernel.org/stable/c/d0006d739738a658a9c29b438444259d9f71dfa0 cve-icon cve-icon
https://git.kernel.org/stable/c/d85a1bec8e8d552ab13163ca1874dcd82f3d1550 cve-icon cve-icon
https://git.kernel.org/stable/c/fb2004bafd1932e08d21ca604ee5844f2b7f212d cve-icon cve-icon
https://lore.kernel.org/linux-cve-announce/2025050113-CVE-2022-49763-3556@gregkh/T cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2022-49763 cve-icon
https://www.cve.org/CVERecord?id=CVE-2022-49763 cve-icon
History

Tue, 17 Jun 2025 16:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-416
Metrics cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

 cvssV3_1

{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}

Fri, 02 May 2025 13:45:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Thu, 01 May 2025 14:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: ntfs: fix use-after-free in ntfs_attr_find() Patch series "ntfs: fix bugs about Attribute", v2. This patchset fixes three bugs relative to Attribute in record: Patch 1 adds a sanity check to ensure that, attrs_offset field in first mft record loading from disk is within bounds. Patch 2 moves the ATTR_RECORD's bounds checking earlier, to avoid dereferencing ATTR_RECORD before checking this ATTR_RECORD is within bounds. Patch 3 adds an overflow checking to avoid possible forever loop in ntfs_attr_find(). Without patch 1 and patch 2, the kernel triggersa KASAN use-after-free detection as reported by Syzkaller. Although one of patch 1 or patch 2 can fix this, we still need both of them. Because patch 1 fixes the root cause, and patch 2 not only fixes the direct cause, but also fixes the potential out-of-bounds bug. This patch (of 3): Syzkaller reported use-after-free read as follows: ================================================================== BUG: KASAN: use-after-free in ntfs_attr_find+0xc02/0xce0 fs/ntfs/attrib.c:597 Read of size 2 at addr ffff88807e352009 by task syz-executor153/3607 [...] Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:317 [inline] print_report.cold+0x2ba/0x719 mm/kasan/report.c:433 kasan_report+0xb1/0x1e0 mm/kasan/report.c:495 ntfs_attr_find+0xc02/0xce0 fs/ntfs/attrib.c:597 ntfs_attr_lookup+0x1056/0x2070 fs/ntfs/attrib.c:1193 ntfs_read_inode_mount+0x89a/0x2580 fs/ntfs/inode.c:1845 ntfs_fill_super+0x1799/0x9320 fs/ntfs/super.c:2854 mount_bdev+0x34d/0x410 fs/super.c:1400 legacy_get_tree+0x105/0x220 fs/fs_context.c:610 vfs_get_tree+0x89/0x2f0 fs/super.c:1530 do_new_mount fs/namespace.c:3040 [inline] path_mount+0x1326/0x1e20 fs/namespace.c:3370 do_mount fs/namespace.c:3383 [inline] __do_sys_mount fs/namespace.c:3591 [inline] __se_sys_mount fs/namespace.c:3568 [inline] __x64_sys_mount+0x27f/0x300 fs/namespace.c:3568 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd [...] </TASK> The buggy address belongs to the physical page: page:ffffea0001f8d400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7e350 head:ffffea0001f8d400 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888011842140 raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88807e351f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88807e351f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88807e352000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807e352080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807e352100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Kernel will loads $MFT/$DATA's first mft record in ntfs_read_inode_mount(). Yet the problem is that after loading, kernel doesn't check whether attrs_offset field is a valid value. To be more specific, if attrs_offset field is larger than bytes_allocated field, then it may trigger the out-of-bounds read bug(reported as use-after-free bug) in ntfs_attr_find(), when kernel tries to access the corresponding mft record's attribute. This patch solves it by adding the sanity check between attrs_offset field and bytes_allocated field, after loading the first mft record.
Title ntfs: fix use-after-free in ntfs_attr_find()
References
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-05-04T08:44:51.803Z

Reserved: 2025-04-16T07:17:33.804Z

Link: CVE-2022-49763

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-05-01T15:15:59.047

Modified: 2025-05-02T13:53:20.943

Link: CVE-2022-49763

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-05-01T00:00:00Z

Links: CVE-2022-49763 - Bugzilla

cve-icon OpenCVE Enrichment

No data.