Mark Zuckerberg Facebook made a bombshell admission about the security of its users personal information on Wednesday in a startling revelation thats almost certain to worsen the privacy crisis currently hanging over the worlds largest social network Most of Facebooks 2 billion users may have had their personal data skimmed from the site by malicious actors the company said in a blog post by Chief Technology Officer Mike Schroepfer Facebook said it has disabled the feature in its sites search function that enabled the data scrapping but the fact that so much user data may have been vulnerable was another setback to the companys efforts to restore confidence with users Meanwhile up to 87 million users may have been affected by the leak of personal information to Trump-linked data firm Cambridge Analytica a number that was much bigger than previous estimates Facebook has been reeling since a whistleblower disclosed that Cambridge Analytica had managed to get hold of user data and used it to target voters with emotional and divisive messages during the 2016 Trump presidential campaign Schroepfer disclosed the new information about privacy compromises on Wednesday in a post describing changes the company has made to its service to better protect users personal data We believe these changes will better protect peoples information while still enabling developers to create useful experiences he said in the post We know we have more work to do and well keep you updated as we make more changes A reverse search feature that could yield a treasure trove of information Schroepfer described how malicious actors had abused Facebooks search feature to scrape personal info about users The search tool allowed anyone to look up a users public Facebook profile information which can include things like gender and birthdate by searching on only the persons phone number or email address The feature was useful in other countries where it may be difficult to type in a users full name Shroepfer said But the tool was abused by bad actors who were able to use it to easily find personal details on potentially billions of Facebook users User information like names hometowns and birth dates is valuable to bad actors who can use it for everything from identity theft to credit card fraud Given the scale and sophistication of the activity weve seen we believe most people on Facebook could have had their public profile scraped in this way Schroepfer said So we have now disabled this feature Were also making changes to account recovery to reduce the risk of scraping as well Schroepfers post was published just an hour before Facebook CEO Mark Zuckerberg is scheduled to hold a press conference with reporters Facebook has been reeling since a whistleblower disclosed that Cambridge Analytica which assisted President Trumps election campaign gleaned data on millions of Facebook users through an app written by a university researcher Only 270 000 Facebook users actually installed the app but due to Facebooks data sharing policies at the time the app was able to gather data on millions of their friends The initial estimates were that the app gathered data on some 50 million Facebook users But Schroepfer revised that number upward by 74 Facebook will be rolling out a new feature on Monday that will inform users who were affected by the data leak See Also SEE ALSO Facebook says you have control over your personal information but you dont really