RIOT is an open-source microcontroller operating system designed for Internet of Things devices and other embedded systems

Overview

RIOT is an open-source microcontroller operating system designed for Internet of Things devices and other embedded systems. In 2026.07 and earlier, _receive() in sys/net/gnrc/network_layer/sixlowpan/gnrc_sixlowpan.c can route an undersized packet into SFF fragment handling after only a minimal payload check. The code then interprets the packet as a sixlowpan_frag_t or larger fragment header without verifying that the packet snip contains the required bytes. A remote attacker can send a malformed 6LoWPAN fragment that causes gnrc_sixlowpan_frag_recv() to read beyond the packet buffer, potentially disclosing memory and crashing the network stack. No fixed repository release is available as of this review.

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.