# CVE-2026-75084: Out-of-bounds write in the TI CC1200 IEEE 802.15.4 driver from an unvalidated radio-supplied packet length

Status: published. Published: 2026-10-14. Updated: 2026-11-04.

The CC1200 sub-GHz IEEE 802.15.4 driver takes the PHY packet length from the first byte of the radio's RX FIFO in get_packet_length() and validates it in verify_rxfifo_validity() (drivers/ieee802154/ieee802154_cc1200.c). That validation only enforced a lower bound (pkt_len < 3); its second clause rejects a FIFO that holds more bytes than declared and therefore never bounds large values. Because the driver configures the radio for variable packet length with PKT_LEN = 0xFF, the length byte is an over-the-air value of 0-255 that reached net_pkt_rx_alloc_with_buffer() and the subsequent SPI burst read unclamped.

An unauthenticated attacker within radio range can transmit a frame that presents a length byte above the IEEE 802.15.4 maximum of 127 while the chip's 128-byte RX FIFO has not overflowed, so the driver's RX_FIFO_ERROR pre-check does not fire. Reaching this state depends on RF framing and timing, since the RX thread is driven off the PKT_SYNC_RXTX signal and may sample the FIFO before a packet is complete; no pairing, authentication, or user interaction is required.

With the default CONFIG_NET_BUF_FIXED_DATA_SIZE and CONFIG_NET_BUF_DATA_SIZE=128, an allocation larger than one fragment is satisfied by a chain of fragments, but read_rxfifo_content() performs a single SPI burst of pkt_len bytes into the first fragment's buf->data and then calls net_buf_add() with the same length. A length above 128 therefore writes up to 127 bytes past the end of a fragment in the contiguous rx_bufs pool and leaves a net_buf whose len exceeds its capacity. The overflowing bytes are FIFO-underflow output rather than attacker-chosen data, so the practical impact is network-buffer-pool corruption and crashes rather than a controlled write. Only builds that enable CONFIG_IEEE802154_CC1200 with an attached CC1200 radio are affected.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: zephyr) — https://github.com/zephyrproject-rtos/zephyr/commit/26a8b8294bf28523c7aa2f15cf728517980ee593

## Affected products and versions

- zephyrproject / zephyr (zephyr): ≥ 1.11.0; < 4.3.2 (affected, semver); ≥ 4.4.0; < 4.5.0 (affected, semver). Source: CNA: zephyr

## Severity and prioritization

- CVSS 3.1: 6.8 (medium); CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H; source: CNA: zephyr

- CVSS 3.1: 6.8 (medium); CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H; source: NVD: vulnerabilities@zephyrproject.org

- CISA KEV: No listing in collected sources

- EPSS: 0.29% as of 2026-11-03; percentile 21.17%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-787

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/zephyrproject-rtos/zephyr/commit/26a8b8294bf28523c7aa2f15cf728517980ee593 (CNA: zephyr; patch)

- https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-pgg5-wwxw-vmj8 (CNA: zephyr)

- https://github.com/zephyrproject-rtos/zephyr/commit/26a8b8294bf28523c7aa2f15cf728517980ee593 (vulnerabilities@zephyrproject.org)

- https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-pgg5-wwxw-vmj8 (vulnerabilities@zephyrproject.org)

## Provenance

- CNA: zephyr: https://www.cve.org/CVERecord?id=CVE-2026-75084; retrieved 2026-11-04; source updated 2026-11-04

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-75084; retrieved 2026-11-04; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-75084; retrieved 2026-11-04; source updated Not reported

Revision: 3f56c3e849f56bcbb9e7aed56e952c5b4767f73db178d257e32ece611c9a99c0

Canonical: https://y2.dev/cve/CVE-2026-75084

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