BETHESDA, MD – November 30, 2018 – Marriott has taken measures to investigate and address a data security incident involving the Starwood guest reservation database.  On November 19, 2018, the investigation determined that there was unauthorized access to the database, which contained guest information relating to reservations at Starwood properties* on or before September 10, 2018.

https://marriott.gcs-web.com/news-releases/news-release-details/marriott-announces-starwood-guest-reservation-database-security