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, accessing and acquiring information between May 27 and May 30, 2023. The company discovered the incident on June 1, 2023. Affected data includes personal and health information. The company engaged forensic experts, notified law enforcement, and is offering 24 months of identity monitoring.