---
id: CVE-2026-23448
title: 'net: usb: cdc_ncm: add ndpoffset to NDP16 nframes bounds check'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net: usb: cdc_ncm: add ndpoffset to NDP16 nframes bounds check

  cdc_ncm_rx_verify_ndp16() validates that the NDP header and its DPE
  entries fit within the skb. The firs…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= ff06ab13a4ccae4acb44a2d4e3ece367b616ab50 <
    63c35b8fce77a7892e8fa06c540d4943145506eb
  - >-
    Linux >= ff06ab13a4ccae4acb44a2d4e3ece367b616ab50 <
    f1c7701d3ac91b62d672c13690cf295821f0d5c3
  - >-
    Linux >= ff06ab13a4ccae4acb44a2d4e3ece367b616ab50 <
    789204f980730258c983102c027c375238009c80
  - >-
    Linux >= ff06ab13a4ccae4acb44a2d4e3ece367b616ab50 <
    403f94ddcb36c552fbef51dea735b131e3dcde8b
  - >-
    Linux >= ff06ab13a4ccae4acb44a2d4e3ece367b616ab50 <
    dce9dda0e3707e887977db44407989e9ead26611
  - >-
    Linux >= ff06ab13a4ccae4acb44a2d4e3ece367b616ab50 <
    2aa8a4fa8d5b7d0e1ebcec100e1a4d80a1f4b21a
  - Linux 3.8
published: '2026-04-03'
updated: '2026-09-14'
sourceUpdated: '2026-09-14T11:58:15.009Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-23448'
references:
  - url: 'https://git.kernel.org/stable/c/63c35b8fce77a7892e8fa06c540d4943145506eb'
  - url: 'https://git.kernel.org/stable/c/f1c7701d3ac91b62d672c13690cf295821f0d5c3'
  - url: 'https://git.kernel.org/stable/c/789204f980730258c983102c027c375238009c80'
  - url: 'https://git.kernel.org/stable/c/403f94ddcb36c552fbef51dea735b131e3dcde8b'
  - url: 'https://git.kernel.org/stable/c/dce9dda0e3707e887977db44407989e9ead26611'
  - url: 'https://git.kernel.org/stable/c/2aa8a4fa8d5b7d0e1ebcec100e1a4d80a1f4b21a'
tags:
  - cve.org
epss: 0.00129
epssPercentile: 0.02937
ingestedAt: '2026-09-14T15:23:07.459Z'
---

## Overview

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

net: usb: cdc_ncm: add ndpoffset to NDP16 nframes bounds check

cdc_ncm_rx_verify_ndp16() validates that the NDP header and its DPE
entries fit within the skb. The first check correctly accounts for
ndpoffset:

  if ((ndpoffset + sizeof(struct usb_cdc_ncm_ndp16)) > skb_in->len)

but the second check omits it:

  if ((sizeof(struct usb_cdc_ncm_ndp16) +
       ret * (sizeof(struct usb_cdc_ncm_dpe16))) > skb_in->len)

This validates the DPE array size against the total skb length as if
the NDP were at offset 0, rather than at ndpoffset. When the NDP is
placed near the end of the NTB (large wNdpIndex), the DPE entries can
extend past the skb data buffer even though the check passes.
cdc_ncm_rx_fixup() then reads out-of-bounds memory when iterating
the DPE array.

Add ndpoffset to the nframes bounds check and use struct_size_t() to
express the NDP-plus-DPE-array size more clearly.

## Affected

- `Linux >= ff06ab13a4ccae4acb44a2d4e3ece367b616ab50 < 63c35b8fce77a7892e8fa06c540d4943145506eb`
- `Linux >= ff06ab13a4ccae4acb44a2d4e3ece367b616ab50 < f1c7701d3ac91b62d672c13690cf295821f0d5c3`
- `Linux >= ff06ab13a4ccae4acb44a2d4e3ece367b616ab50 < 789204f980730258c983102c027c375238009c80`
- `Linux >= ff06ab13a4ccae4acb44a2d4e3ece367b616ab50 < 403f94ddcb36c552fbef51dea735b131e3dcde8b`
- `Linux >= ff06ab13a4ccae4acb44a2d4e3ece367b616ab50 < dce9dda0e3707e887977db44407989e9ead26611`
- `Linux >= ff06ab13a4ccae4acb44a2d4e3ece367b616ab50 < 2aa8a4fa8d5b7d0e1ebcec100e1a4d80a1f4b21a`
- `Linux 3.8`

## Remediation

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