Around 96% of all Twitter for Android users already have installed security protections, Twitter said. But the other 4% are vulnerable to attackers through outside apps accessing private data on their devices.
Read more: Lock down your Twitter security settings now
Twitter said it doesn't have evidence that this vulnerability has been exploited by attackers, but the company is encouraging users to update to the latest version of Twitter for Android to be safe. Twitter is also sending in-app notices to anyone who could've been vulnerable, the company said.
Twitter said it didn't find similar vulnerabilities in its iOS app or on its website.
Google confirmed the issue was related to an Android vulnerability fixed back in October 2018.