---
id: CVE-2026-75083
title: >-
  The receive path of the NXP KW41Z IEEE 802.15.4 driver, kw41z_rx() in
  drivers/ieee802154/ieee802154_kw41z.c, computed the payload size as pkt_len =
  len - KW41Z_FCS_LENGTH in a uint8_t, where len is the frame length reported by
  the radio.…
summary: >-
  The receive path of the NXP KW41Z IEEE 802.15.4 driver, kw41z_rx() in
  drivers/ieee802154/ieee802154_kw41z.c, computed the payload size as pkt_len =
  len - KW41Z_FCS_LENGTH in a uint8_t, where len is the frame length reported by
  the radio.…
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H'
cwe:
  - CWE-191
published: '2026-10-14'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T17:19:10.307'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-75083'
references:
  - url: >-
      https://github.com/zephyrproject-rtos/zephyr/commit/51d71864578c08eb1a1201f87b46ec81c8609d62
    label: vulnerabilities@zephyrproject.org
  - url: >-
      https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-2pwx-gg6f-535f
    label: vulnerabilities@zephyrproject.org
tags:
  - nvd
ingestedAt: '2026-10-14T17:44:53.676Z'
---

## Overview

The receive path of the NXP KW41Z IEEE 802.15.4 driver, kw41z_rx() in drivers/ieee802154/ieee802154_kw41z.c, computed the payload size as pkt_len = len - KW41Z_FCS_LENGTH in a uint8_t, where len is the frame length reported by the radio. The interrupt handler kw41z_isr() obtained that length from the RX_FRAME_LENGTH field of the ZLL IRQSTS register — a copy of the PHY header length byte of the frame received over the air — and only rejected the value zero. A reported length of one therefore underflowed to pkt_len == 255.

Because the packet is allocated with NET_AF_UNSPEC on a non-Ethernet L2, net_pkt_rx_alloc_with_buffer() does not clamp the request to the interface MTU; with the default fixed-size buffer pool (CONFIG_NET_BUF_FIXED_DATA_SIZE, CONFIG_NET_BUF_DATA_SIZE=128) the allocation succeeded as a chain of two fragments. The subsequent register-to-buffer copy loops write into the first fragment only, so 255 bytes were written into a 128-byte net_buf data block, overrunning it by up to 127 bytes into adjacent network-buffer-pool memory, and reading up to 128 bytes past the end of the radio's PKT_BUFFER_RX register array.

The length field originates from an unauthenticated frame transmitted by any device within 802.15.4 radio range, and is captured by the hardware at PHY-header time — before frame filtering has completed — while the handler samples it after clearing the interrupt status, so an attacker flooding frames with a length byte of one can drive the underflow. The impact is memory corruption in the shared receive buffer pool from interrupt context, most plausibly a crash or corruption of other packets' data; the overflowing bytes are radio register contents rather than attacker-authored data, which bounds the integrity impact.

The fix rejects any length below KW41Z_FCS_LENGTH and additionally verifies net_buf_tailroom() of the first fragment before the copy loops, which also covers the CONFIG_NET_L2_OPENTHREAD variant of the size computation.

## Remediation

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