In a statement on the company's blog, NGP VAN CEO Stu Trevelyan apologized to the Clinton and Sanders campaigns and explained how the data was able to be viewed:

"On Wednesday morning, there was a release of VAN code. Unfortunately, it contained a bug. For a brief window, the voter data that is always searchable across campaigns in VoteBuilder included client scores it should not have, on a specific part of the VAN system. So for voters that a user already had access to, that user was able to search by and view (but not export or save or act on) some attributes that came from another campaign.&quot some attributes that came from another campaign."