CVE-2026-98136

Summary

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.

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/3e2ae47b8ebc632c27e7843a4632d9a7c060885e
• https://git.kernel.org/stable/c/c8504fc1245f5322af5fa5c325ab05f9cf792b87

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