With almost 70 percent of its population on Facebook, Vietnam was the ninth most heavily hit country by the social network's security breach scandal, which involved the personal data of 87 million users worldwide being leaked.
A survey released by Facebook on Wednesday showed the personal data of 427,446 users in Vietnam had been leaked.
As of July 2017, more than 64 million out of 92 million Vietnamese people were using the social media network.
The U.S. stands top of the countries hit hardest, followed by the Philippines, Indonesia and the U.K.
Facebook Inc said on Wednesday that the personal information of up to 87 million users worldwide may have been improperly shared with political consultancy Cambridge Analytica, up from a previous news media estimate of more than 50 million.
Mike Schroepfer, Facebook's chief technology officer, said on Facebook’s newsroom site on Wednesday that starting on Monday, Facebook will show people a link at the top of their News Feed so they can see what apps they use and the information they have shared with those apps.
“People will also be able to remove apps that they no longer want. As part of this process we will also tell people if their information may have been improperly shared with Cambridge Analytica,” he said.
Facebook first acknowledged last month that personal information about millions of users wrongly ended up in the hands of Cambridge Analytica.
Mark Zuckerberg will testify about the matter next week before the U.S. House Energy and Commerce Committee, Reuters reported on Thursday.
London-based Cambridge Analytica, which has counted U.S. President Donald Trump’s 2016 campaign among its clients, disputed Facebook’s estimate of affected users. It said in a tweet on Wednesday that it received no more than 30 million records from a researcher it hired to collect data about people on Facebook.
Zuckerberg, on a call with reporters, said Facebook should have done more to audit and oversee third-party app developers like the one Cambridge Analytica hired in 2014.