Sweden's big breach.
Careless handling of data by Sweden Transportstyrelsen, the country's transportation agency, resulted in exposure of information touching most citizens, and containing some militarily sensitive data. This involves a great deal more information than would be lost in the breach of, say, an American state's department of motor vehicles. The data include weight capacities of roads and bridges (potentially useful to an invader) and the type, model, weight, operators and condition of government and military vehicles (from which, among other things, order of battle could be inferred). There was also much private information at risk, including the names, photos, and home addresses of air force pilots, anyone in police registers, people in witness relocation programs, and members of Swedish special operations forces (Hacker News).
The breach occurred in 2012, was noticed by security services in 2016, and won't be fully remediated until this autumn. The director-general of Transportstyrlesn, Maria Ågren, took the fall for the incident in January: she was fired and fined 70,000 krona (about $8500) for "careless[ness] with secret information" (Dagens Nyheter).
The root cause is being ascribed to failure to properly supervise a $100-million deal with IBM to handle driver's licensing and vehicle registration. The agency failed, apparently, to control what data it handed over, and how the data were controlled. Prime Minister Lofven called the breach of information “a total breakdown,” saying, “It is incredibly serious. It is a violation of the law and put Sweden and its citizens in harm’s way.” The head of the Security Service, Anders Thornberg, said “This is very serious because it could damage our operational business that we are conducting every day in order to protect Sweden.” The scandal is a major one. For Sweden this is probably a more serious matter than such large incidents as the OPM breach were for the US. Some observers think the Transportstyrelsen breach has the potential to bring down the government (New York Times). Two ministers have already resigned over the incident: Anders Ygeman (home affairs) and Anna Johansson (infrastructure) (Politico).