{"id":"CVE-2026-75083","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-75083","generatedAt":"2026-10-28T03:30:33.153Z","title":"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…","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.\n\nBecause 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.\n\nThe 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.\n\nThe 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.","published":"2026-10-14T17:19:10.000Z","lastModified":"2026-10-16T16:21:02.000Z","status":"Awaiting Analysis","sourceIdentifier":"vulnerabilities@zephyrproject.org","cvss":{"version":"3.1","score":5.9,"severity":"MEDIUM","vector":"CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H"},"cwe":["CWE-191"],"affected":[],"epss":{"score":0.00229,"percentile":0.13621,"date":"2026-10-26","history":[{"date":"2026-10-15","score":0.00229,"percentile":0.12746}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.23%). Track it; it rarely justifies an emergency change on its own."},"changes":[{"kind":"new","label":"New CVE","at":"2026-10-14T17:19:10.000Z","detail":{"score":"5.9","severity":"MEDIUM","publishedAt":"2026-10-14T17:19:10.307Z"},"summary":"New CVE, medium severity (CVSS 5.9)."}],"references":[{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/51d71864578c08eb1a1201f87b46ec81c8609d62","source":"vulnerabilities@zephyrproject.org"},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-2pwx-gg6f-535f","source":"vulnerabilities@zephyrproject.org"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-75083","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}