ntfs: bound the attribute-list entry in ntfs_read_inode_mount()
The $MFT attribute-list walk in ntfs_read_inode_mount() validates each
entry only with "(u8 *)al_entry + 6 > al_end" and
"(u8 *)al_entry + le16_to_cpu(al_entry->length) > al_end", but then reads
al_entry->lowest_vcn (an __le64 at offset 8) and al_entry->mft_reference
(offset 16) -- fields beyond the 6 bytes proven in range. al_entry->length
is attacker-controlled and only required non-zero, so a short entry (e.g.
length 8) placed at the tail passes both checks while the lowest_vcn /
mft_reference reads fall past al_end.
al_end is ni->attr_list + attr_list_size (the on-disk size); the buffer is
kvzalloc(round_up(attr_list_size, SECTOR_SIZE)), so the sector rounding
usually absorbs the over-read -- but when attr_list_size is a multiple of
SECTOR_SIZE there is no slack and a crafted $MFT attribute list produces an
out-of-bounds read at mount time.
Validate the entry with ntfs_attr_list_entry_is_valid() (added in patch
1/3) before dereferencing it, matching the bound the other attribute-list
walks now use. The validator already requires the length to cover the fixed
header, which makes the separate "!al_entry->length" check redundant, so
drop it too.
Analysis
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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 |
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| Linux | Linux | affected |
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No vendor fix or workaround currently provided.
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Fri, 04 Sep 2026 17:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: ntfs: bound the attribute-list entry in ntfs_read_inode_mount() The $MFT attribute-list walk in ntfs_read_inode_mount() validates each entry only with "(u8 *)al_entry + 6 > al_end" and "(u8 *)al_entry + le16_to_cpu(al_entry->length) > al_end", but then reads al_entry->lowest_vcn (an __le64 at offset 8) and al_entry->mft_reference (offset 16) -- fields beyond the 6 bytes proven in range. al_entry->length is attacker-controlled and only required non-zero, so a short entry (e.g. length 8) placed at the tail passes both checks while the lowest_vcn / mft_reference reads fall past al_end. al_end is ni->attr_list + attr_list_size (the on-disk size); the buffer is kvzalloc(round_up(attr_list_size, SECTOR_SIZE)), so the sector rounding usually absorbs the over-read -- but when attr_list_size is a multiple of SECTOR_SIZE there is no slack and a crafted $MFT attribute list produces an out-of-bounds read at mount time. Validate the entry with ntfs_attr_list_entry_is_valid() (added in patch 1/3) before dereferencing it, matching the bound the other attribute-list walks now use. The validator already requires the length to cover the fixed header, which makes the separate "!al_entry->length" check redundant, so drop it too. | |
| Title | ntfs: bound the attribute-list entry in ntfs_read_inode_mount() | |
| 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: 2026-09-04T16:48:27.068Z
Reserved: 2026-08-26T14:34:25.798Z
Link: CVE-2026-80869
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-04T17:16:58.750
Modified: 2026-09-04T17:16:58.750
Link: CVE-2026-80869
Redhat
No data.
OpenCVE Enrichment
No data.
No weakness.