RIOT-OS, an operating system that supports Internet of Things devices, contains a network stack with the ability to process 6LoWPAN frames. Prior to version 2022.10, an attacker can send a crafted frame to the device resulting in a NULL pointer dereference. During forwarding of a fragment an uninitialized entry in the reassembly buffer is used. The NULL pointer dereference triggers a hard fault exception resulting in denial of service. Version 2022.10 fixes this issue. As a workaround, disable support for fragmented IP datagrams or apply the patches manually.
The product dereferences a pointer that it expects to be valid but is NULL.