Delta Dental of California and affiliates experienced a data security incident involving the MOVEit Transfer software. Unauthorized actors exploited a previously unknown vulnerability in the software between May 27 and May 30, 2023. The company discovered the incident on June 1, 2023. Personal information, including names, addresses, and potentially health/financial data, was accessed and acquired without authorization. The company engaged forensic experts, notified law enforcement, and is offering 24 months of identity monitoring to affected individuals.