South Korea's Day One Company: stolen GitHub key leads to member data leak across Fastcampus and 7 other brands

According to Yonhap News TV, Day One Company, operator of Fastcampus and other online education brands, said a GitHub master account key was stolen and used for a first intrusion into its services on May 9, 2026 ^[1]. Eight brands including Fastcampus, Coloso and Zerobase are affected, with names, emails, phone numbers and encrypted passwords leaked, plus addresses and job details for some customers ^[1]. The company says no publication or misuse has been seen yet but members should change their account passwords for safety ^[1].

Industries mainly affected: Education

1. Change your password on Day One Company brands ^[1].
2. Change it anywhere else you reused it ^[1].