Reddit announced that its systems were violated in mid-June of 2018. The company reports that the email addresses of most service users have been intercepted as well as some of the passwords from an old data backup prior to 11 years.
According to Reddit, the hack took place between June 14 and June 18 when a hacker managed to break accounts of many employees using 2FA authentication via SMS.
The attacker managed to gain access to old forgotten salted passwords from a backup of the 2007 database and the current Reddit user emails.
Reddit confirmed that the e-mail addresses found in the hacker's hands were through some logs stored on its servers between 3 and 17 June of 2018.
The company also reports that the hacker has managed to intercept the Reddit source code, internal logs and configuration files.
Read the official announcement, and change passwords immediately.