So, if you had a phone number associated with a Twitter account, you're probably part of that massive breach. The media reported 5 million accounts affected in November, but that wasn't entirely accurate. The real figure was more like 7 million at that point. Journalists then claimed another breach affected 17 million, but potentially the figure was much, much higher. Twitter has stated that they had fixed the exploit as of January 2022, but, c'mon. As of December 23rd, they are under investigation by the Irish Data Protection Commission. The 400 million figure posted on HackerNews might not be credible, but we also know that multiple groups have been working together over the past month leaking more and more details, so who knows.

This article is from November: https://9to5mac.com/2022/11/25/massive-twitter-data-breach/

And from 2 days ago: https://www.bleepingcomputer.com/news/security/massive-twitter-data-leak-investigated-by-eu-privacy-watchdog/