uint16_t net_checksum_tcpudp(uint16_t length, uint16_t proto,
                             uint8_t *addrs, uint8_t *buf)
{
    uint32_t sum = 0;

    sum += net_checksum_add(length, buf);         // payload
    sum += net_checksum_add(8, addrs);            // src + dst address
    sum += proto + length;                        // protocol & length
    return net_checksum_finish(sum);
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.