Linux Kernel NTFS $AttrDef Table OOB Read
CVE-2026-98136 Published on September 25, 2026
ntfs: bound $AttrDef table walk to the loaded table size
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.
Products Associated with CVE-2026-98136
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Affected Versions
Linux:- Version 1e9ea7e04472d4e5e12e58c881eaacfb3e49b669 and below 3e2ae47b8ebc632c27e7843a4632d9a7c060885e is affected.
- Version 1e9ea7e04472d4e5e12e58c881eaacfb3e49b669 and below c8504fc1245f5322af5fa5c325ab05f9cf792b87 is affected.
- Version 7.1 is affected.
- Before 7.1 is unaffected.
- Version 7.2.7, <= 7.2.* is unaffected.
- Version 7.3-rc2, <= * is unaffected.