CVE-2026-80673

ntfs: bound the look-ahead attribute-list entry in ntfs_external_attr_find()

Published Aug 28, 2026 CVSS 3.1 · 9.8 Critical EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

ntfs: bound the look-ahead attribute-list entry in ntfs_external_attr_find()

When resolving an attribute lookup with a non-zero @lowest_vcn,
ntfs_external_attr_find() peeks at the next $ATTRIBUTE_LIST entry to
decide whether to keep searching, but bounds that not-yet-validated
entry only with "(u8 *)next_al_entry + 6 < al_end" (which proves just
bytes 0..6 are in range) and "(u8 *)next_al_entry + length <= al_end"
with an attacker-controlled, non-8-aligned length. It then reads
next_al_entry->lowest_vcn (an __le64 at offset 8) and the name at
next_al_entry->name_offset, both of which can lie past al_end -- the
exact end of the kvmalloc'd attribute-list buffer (allocated at the
on-disk attr_list_size, no rounding). A crafted on-disk $ATTRIBUTE_LIST
whose last entry sits a few bytes before al_end therefore yields a slab
out-of-bounds read when the inode is read.

Validate the look-ahead entry with ntfs_attr_list_entry_is_valid() (added
in patch 1/3) before dereferencing lowest_vcn and the name, so the same
fixed-header, length and name bounds the main attribute-list walk uses now
guard this read too.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

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History
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

Type Values Removed Values Added
Weaknesses CWE-125
CWE-20
Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: ntfs: bound the look-ahead attribute-list entry in ntfs_external_attr_find() When resolving an attribute lookup with a non-zero @lowest_vcn, ntfs_external_attr_find() peeks at the next $ATTRIBUTE_LIST entry to decide whether to keep searching, but bounds that not-yet-validated entry only with "(u8 *)next_al_entry + 6 < al_end" (which proves just bytes 0..6 are in range) and "(u8 *)next_al_entry + length <= al_end" with an attacker-controlled, non-8-aligned length. It then reads next_al_entry->lowest_vcn (an __le64 at offset 8) and the name at next_al_entry->name_offset, both of which can lie past al_end -- the exact end of the kvmalloc'd attribute-list buffer (allocated at the on-disk attr_list_size, no rounding). A crafted on-disk $ATTRIBUTE_LIST whose last entry sits a few bytes before al_end therefore yields a slab out-of-bounds read when the inode is read. Validate the look-ahead entry with ntfs_attr_list_entry_is_valid() (added in patch 1/3) before dereferencing lowest_vcn and the name, so the same fixed-header, length and name bounds the main attribute-list walk uses now guard this read too.
Title ntfs: bound the look-ahead attribute-list entry in ntfs_external_attr_find()
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Aug 29, 2026, 6:22 AM
Reserved
Aug 26, 2026, 2:34 PM
Status
Received
Published
Aug 28, 2026, 8:16 AM
Modified
Aug 29, 2026, 7:16 AM
Severity
Moderate
Public date
Aug 28, 2026, 12:00 AM