Thousands of sensitive emails from the National Republican Congressional Committee (NRCC) were stolen in a hack earlier this year, exposing emails of four senior aides to an outsider for months, three party officials told Politico and an NRCC spokesperson confirmed to Axios.

The big picture: The NRCC was alerted by its cybersecurity vendor of the intrusion, which was uncovered in April — just seven months before the 2018 midterm elections. GOP House leadership, including House Speaker Paul Ryan and House Majority Leader Kevin McCarthy, were not alerted of the hack until this week, when Politico reached out to the NRCC about the incident.