---
id: CVE-2026-72197
title: 'fs/ntfs3: bound DeleteIndexEntryAllocation memmove length'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  fs/ntfs3: bound DeleteIndexEntryAllocation memmove length

  In do_action()'s DeleteIndexEntryAllocation case, e->size comes
  from an on-disk INDEX_BUFFER entry.  When e->…
severity: high
cvss: 8.4
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 <
    c38ed2ab62fab75fd6d0fdc2bee540fbebc7b959
  - >-
    Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 <
    b509b9613f20dc5b653d54bf78fab00d79cc43c8
  - >-
    Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 <
    4c8aac931c1cd70347961ba5157aa916448c6a25
  - >-
    Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 <
    f383aae59ec3994c14804f4191c59038b206be81
  - >-
    Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 <
    09fddd52c1b0cef2c086d61be8f3d5dc92e36565
  - >-
    Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 <
    554700c65d398276cb00a8ef95f1d5e00b9eff93
  - >-
    Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 <
    fc4626bb3656362de8b0ecd56605d47a19ec3518
  - Linux 5.15
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T18:43:48.330736Z'
published: '2026-08-15'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T18:45:01.720Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-72197'
references:
  - url: 'https://git.kernel.org/stable/c/c38ed2ab62fab75fd6d0fdc2bee540fbebc7b959'
  - url: 'https://git.kernel.org/stable/c/b509b9613f20dc5b653d54bf78fab00d79cc43c8'
  - url: 'https://git.kernel.org/stable/c/4c8aac931c1cd70347961ba5157aa916448c6a25'
  - url: 'https://git.kernel.org/stable/c/f383aae59ec3994c14804f4191c59038b206be81'
  - url: 'https://git.kernel.org/stable/c/09fddd52c1b0cef2c086d61be8f3d5dc92e36565'
  - url: 'https://git.kernel.org/stable/c/554700c65d398276cb00a8ef95f1d5e00b9eff93'
  - url: 'https://git.kernel.org/stable/c/fc4626bb3656362de8b0ecd56605d47a19ec3518'
tags:
  - cve.org
epss: 0.00185
epssPercentile: 0.07565
ingestedAt: '2026-10-16T19:46:24.422Z'
---

## Overview

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

fs/ntfs3: bound DeleteIndexEntryAllocation memmove length

In do_action()'s DeleteIndexEntryAllocation case, e->size comes
from an on-disk INDEX_BUFFER entry.  When e->size makes
e + e->size point past hdr + hdr->used,
PtrOffset(e1, Add2Ptr(hdr, used)) returns a negative ptrdiff_t
that is silently cast to a quasi-infinite size_t when passed
to memmove().  The memmove then walks past the destination
buffer.

The sibling DeleteIndexEntryRoot case at fslog.c:3540-3543
already carries the corresponding guard:

	if (PtrOffset(e1, Add2Ptr(hdr, used)) < esize ||
	    Add2Ptr(e, esize) > Add2Ptr(lrh, rec_len) ||
	    used + esize > le32_to_cpu(hdr->total)) {
		goto dirty_vol;
	}

Apply the same shape to the allocation-path case.  Also reject
esize == 0: memmove(e, e, ...) is a no-op and leaves
hdr->used unchanged, hiding a malformed entry from the
existing check_index_header() walk.

Reproduced under UML+KASAN on mainline 8d90b09e6741 by
mounting a crafted NTFS image: the unguarded memmove takes a
length of 0xffffffffffffff00 and the kernel oopses in
memmove+0x81/0x1a0 on the do_action+0x36a2 frame.

[almaz.alexandrovich@paragon-software.com: clang-formatted the changes]

## Affected

- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < c38ed2ab62fab75fd6d0fdc2bee540fbebc7b959`
- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < b509b9613f20dc5b653d54bf78fab00d79cc43c8`
- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 4c8aac931c1cd70347961ba5157aa916448c6a25`
- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < f383aae59ec3994c14804f4191c59038b206be81`
- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 09fddd52c1b0cef2c086d61be8f3d5dc92e36565`
- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 554700c65d398276cb00a8ef95f1d5e00b9eff93`
- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < fc4626bb3656362de8b0ecd56605d47a19ec3518`
- `Linux 5.15`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.