A data breach broker is selling a database that allegedly contains 25 million Mathway user records on a dark web marketplace for $4,000. Mathway is a calculator that allows users to type in math questions and receive an answer for free. The Mathway app is top-rated, with over 10 million installs on Android and ranked as #4 under education in the Apple Store. Cyber intelligence firm Cyble told BleepingComputer that they were tracking a potential data breach of Mathway earlier this month.
Source: https://www.bleepingcomputer.com/news/security/mathway-investigates-data-breach-after-25m-records-sold-on-dark-web/