Hackers exploited a high-severity vulnerability in the open source Salt management framework that was disclosed to the public on April 30, a day after maintainers released new versions that fixed the issue. In all, the intrusion affected the following services: mail servers, download mirrors, statistics, the download portal, and the Gerrit Code Review system used in development. Sunday morning at 3 a.m. the LineageOS team managed to restore the website, email, wiki, and some internal services.
Source: https://www.bleepingcomputer.com/news/security/lineageos-outage-caused-by-hackers-breaching-main-infrastructure/