Linux Kernel NTFS attrdef Parser Reads Past a Short Attribute-Definition Table, Triggering Out-of-Bounds Access

Status: UPDATED  |  Advisory ID: CVE-2026-98136

Key Details

Affected Products, Subsystems & Sectors

What to Know

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

ntfs: bound $AttrDef table walk to the loaded table size

ntfs_attr_find_in_attrdef() walks the in-memory $AttrDef table, but the

loop condition bounds only the start of each entry, not the whole entry:

for (ad = vol->attrdef; (u8 *)ad - (u8 *)vol->attrdef <

vol->attrdef_size && ad->type; ++ad)

struct attr_def is 160 bytes; the guard reads ad->type at offset 128 and

the loop body reads further fields. vol->attrdef is kvzalloc(i_size),

where i_size is the on-disk $AttrDef data size, checked in

load_and_init_attrdef() only as 0 < i_size <= 0x7fffffff. A volume whose

$AttrDef data size is smaller than one entry (e.g. 120 bytes) makes the

read of ad->type run past the allocation. Creating a file reaches this

through ntfs_attr_size_bounds_check() and reads out of bounds:

BUG: KASAN: slab-out-of-bounds in ntfs_attr_find_in_attrdef+0x66/0xa0

Read of size 4 at addr ffff888005833280 by task init/1

ntfs_attr_find_in_attrdef

ntfs_attr_size_bounds_check

ntfs_attr_can_be_non_resident

ntfs_attr_add

Require the whole entry to lie within attrdef_size in the loop guard, and

reject at mount a $AttrDef too small to hold one attr_def entry. (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References