Private information on 600,000 Alaska voters was exposed on the internet, though the data firm TargetSmart said it was only accessed by the security researcher who identified the data breach.
TargetSmart, which works with the Alaska Democratic Party, said in a statement that it had given another company, Minnesota-based Equals3, access to the voter data, which was then "inadvertently exposed."
The exposed data, which was taken offline Monday, includes some sensitive personal information like birth dates, household income, marital status and ethnic identity, according to the technology website ZDNet.
TargetSmart didn't say how long the data was exposed on the internet, only that it was "for a time." It asserted that the file was never improperly accessed.
"Equals3 assures us that although the data was left exposed for a time, it has since been taken offline and secured," TargetSmart said in a prepared statement.
Josie Bahnke, Alaska's elections director, said the state hadn't turned over private data in the first place.
Parties and political operatives frequently request the state's full public voter file to help them identify and persuade potential supporters. But the state only turns over data that's not deemed to be "confidential" — which means that information like dates of birth would have to be obtained by other sources.
Companies, retail outlets and political operatives often purchase non-public information from commercial sources and merge it with public data like voter rolls. For political use, the enhanced database can be used by candidates and campaigns to make personally tailored pitches to voters.
Last month, Lt. Gov. Byron Mallott, who oversees Alaska's elections, cited the confidentiality of certain state data when he refused to turn over information like driver's license numbers, places of birth and Social Security numbers to a voter fraud panel convened by President Donald Trump.
Other data that was inadvertently exposed by Equals3, like income levels, isn't even part of the state's voter file, Bahnke said.
The Alaska Democrats still plan to keep working with TargetSmart, said Jay Parmley, the party's executive director. He said he'd been on multiple phone calls with the firm Thursday.
"They're taking it very seriously," he said.