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CVE-2026-75083— Integer underflow of the radio-reported frame length causes an out-of-bounds write in the NXP KW41Z IEEE 802.15.4 driver

Quick assessment

Affected
zephyrproject zephyr
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

NXP KW41Z IEEE 802.15.4 驱动程序的接收路径 （位于 ）在计算载荷大小时，使用了无符号 8 位整数（ ）执行 ，其中 是由无线电硬件报告的帧长度。中断处理函数 从 ZLL IRQSTS 寄存器的 字段获取该长度值——该字段是空中接收到的帧的物理层（PHY）头部长度字节的副本——并且仅对值为零的情况进行拒绝。当报告的长度为 1 时，会导致无符号整数下溢，使得 变为 255。 由于在以太网第二层（L2）之外使用 分配数据包，函数 不会将请求限制接口的最大传输单元（MTU）；在采用默认固定大小缓冲区

CVSS 5.9 · Medium EPSS 0.23% · P13

Affected Version Matrix 1

VendorProduct Version RangeStatus
zephyrproject zephyr 1.8.0< 4.5.0 affected
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I. Basic Information for CVE-2026-75083

Vulnerability Information
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Vulnerability Title
Integer underflow of the radio-reported frame length causes an out-of-bounds write in the NXP KW41Z IEEE 802.15.4 driver
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
整数下溢(超界折返)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
zephyrproject zephyr 1.8.0 ~ 4.5.0 -

II. Public POCs for CVE-2026-75083

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III. Intelligence Information for CVE-2026-75083

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Patches & Fixes for CVE-2026-75083 (1)

Other References for CVE-2026-75083 (1)

Same Patch Batch · zephyrproject · 2026-10-14 · 4 CVEs total

CVE-2026-19673 7.1 HIGH Out-of-bounds read and net_buf length underflow in Zephyr Ethernet L2 when parsing a trunc
CVE-2026-75084 6.8 MEDIUM Out-of-bounds write in the TI CC1200 IEEE 802.15.4 driver from an unvalidated radio-suppli
CVE-2026-75085 4.2 MEDIUM Out-of-bounds read from received-frame length underflow in the STM32WBA IEEE 802.15.4 driv

IV. Related Vulnerabilities

Same product: zephyr
Same vendor: zephyrproject
Same weakness: CWE-191

V. Comments for CVE-2026-75083

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