Google’s Project Zero discovered that a security flaw might have allowed hackers to eavesdrop on Android users. After an investigation conducted by cybersecurity researcher Natalie Silvanovich, the expert discovered vulnerabilities in many apps with 10M+ installs on Google Play that accept incoming calls. The affected applications include hugely popular apps such as Facebook Messenger, Signal, Google Duo, JioChat, and Mocha. She described her findings in a Project Zero blog post.