In reading the headline I was expecting they would explain it within the first few paragraphs but instead buried what the kid did in the last 5 sentences of the article.
Like most of us though still alarms me that these machines are in use and have some easily exploitable vulnerabilities but as mentioned by one of the vendors in the article some/most of these exploits require physical access to the voting machine. Not to take way from the exploits but it would be pretty obvious if someone was doing this (plugging a device into the voting machine) on election day.