Integer underflow of the radio-reported frame length causes an out-of-bounds write in the NXP KW41Z IEEE 802.15.4 driver
Summary
| CVE | CVE-2026-75083 |
|---|---|
| State | PUBLISHED |
| Assigner | zephyr |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-10-14 17:19:10 UTC |
| Updated | 2026-10-16 16:21:02 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 5.9 MEDIUM from [email protected]
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
EPSS: 0.002290000 probability, percentile 0.127740000 (date 2026-10-16)
Problem Types: CWE-191 | CWE-191 integer-overflow
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 5.9 | MEDIUM | CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H |
| 3.1 | CNA | CVSS | 5.9 | MEDIUM | CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H |
CVSS v3.1 Breakdown
Attack Vector
AdjacentAttack Complexity
HighPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
LowAvailability
HighCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Zephyrproject | Zephyr | affected 1.8.0 4.5.0 semver | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/zephyrproject-rtos/zephyr/commit/51d71864578c08eb1a1201f87b46... | [email protected] | github.com | |
| github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-2pwx-gg6f-... | [email protected] | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.