I have read the lawsuit, and it accuses Facebook of making false and misleading statements in their data privacy policy. It takes issue with this section of Facebook's privacy policy:

While you are allowing us to use the information we receive about you, you always own all of your information. Your trust is important to us, which is why we don't share information we receive about you with others unless we have:

• received your permission;

• given you notice, such as by telling you about it in this policy; or

• removed your name and any other personally identifying information from it.

The lawsuit claims Facebook violated bullet points 1 and 2, citing the CA news. The lawsuit uses this point to argue Facebook lied to their investors, did not provide more information on this in their SEC filings, and that investors suffering financial loss when the stock price fell after CA news.