The vulnerability allows attacker to insert malicious code into restricted storage areas of the Twitter app, which make possible for bad actor to access information (e.g., Direct Messages, protected Tweets, location information) from the app.
On the advisory Twitter says-
We don’t have evidence that malicious code was inserted into the app or that this vulnerability was exploited, but we can’t be completely sure so we are taking extra caution.Furthermore, Twitter says they will notify all the affected users through the Twitter app or by email with specific instructions to keep them safe. These instructions vary based on what versions of Android and Twitter for Android people are using.
So we recommend all our readers to immediately update their Twitter app from playstore.