# CVE-2026-18415: Zephyr IEEE 802.15.4 buffer overflow in ieee802154_send()

Source: https://junglewise.ai/threats/cve-2026-18415-ieee802154-send-in-subsys-net-l2-ieee802154-ieee802154-c-copies  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-28. Updated: 2026-09-28  
License: CC BY 4.0 with a link back

CVE-2026-18415 · Severity: medium · CVSS 6.3 · Published 2026-09-28

Zephyr's IEEE 802.15.4 network stack contains a buffer overflow vulnerability in the transmit path when handling raw or datagram sockets. An unprivileged application can send an oversized packet that writes beyond a 125-byte transmit buffer, corrupting adjacent kernel memory and potentially causing a crash or further compromise of the system.

Technologies: [Zephyr RTOS](https://junglewise.ai/threats/technologies/rtos). Vendors: [Zephyr](https://junglewise.ai/threats/vendors/zephyr).

## Quick answers

**Is CVE-2026-18415 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-18415 being exploited in the wild.

**How severe is CVE-2026-18415?** Medium severity, with a CVSS score of 6.3, published 28 September 2026.

**Which products and versions are affected?** Zephyr RTOS affected versions with CONFIG_NET_L2_IEEE802154_FRAGMENT enabled (default when CONFIG_NET_6LO is set).

**Is there a fix for CVE-2026-18415?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-18415 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2026-18415?** Check whether you run Zephyr RTOS at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The ieee802154_send() function in subsys/net/l2/ieee802154/ieee802154.c copies outgoing packets into a fixed 125-byte transmit buffer without validating packet length when 6LoWPAN fragmentation is not required. The vulnerability is reachable through NET_AF_PACKET sockets (both RAW and DGRAM types) which bypass the length validation that applies to NET_AF_INET6 packets. An attacker with local access or unprivileged thread privileges can trigger an out-of-bounds write by sending a crafted packet.

## Affected products

- Zephyr Zephyr RTOS affected versions with CONFIG_NET_L2_IEEE802154_FRAGMENT enabled (default when CONFIG_NET_6LO is set)

## Timeline

- 2026-09-28: disclosed

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