But more alarming was the admission that practically all two billion of its users could have had their data scraped due to "features" on the website.
In a blog post, chief technology officer Mike Schroepfer wrote: "Given the scale and sophistication of the activity we’ve seen, we believe most people on Facebook could have had their public profile scraped in this way."
Schroepfer made this admission when detailing a number of steps that he said the company was taking to cut down on data accessibility by third parties.
The company contested this, saying that the data exfiltration was due to a feature in an app. The allegations about Cambridge Analytica were made by a former employee, Christopher Wylie, and reported by London's The Observer and The New York Times over the weekend of 17/18 March.
The data was collected in 2014 by Aleksandr Kogan, a researcher, using an app that requested people to take a personality test for academic research.
According to the post by Schroepfer, of the Facebook users whose data was obtained by Cambridge Analytica, nearly 81% were American - a total of 70.6 million.
Schroepfer said changes would be made to the events API, the groups API, the pages API, the Facebook login, the Instagram platform API, call and text history, data providers and partner category and app controls to prevent data leaking out.
Details of these changes were provided in another blog post.
Facebook chairman Mark Zuckerberg is due to face the US Congress during a series of hearings next week. The UK parliament requested that Zuckerberg make an appearance there as well, but he rejected the request.