$uck it, Zuck!

Covert Web-to-App Tracking via Localhost on Android (via zeropartydata.es).

We disclose a novel tracking method by Meta and Yandex potentially affecting billions of Android users. We found that native Android apps—including Facebook, Instagram, and several Yandex apps including Maps and Browser—silently listen on fixed local ports for tracking purposes. (…) This web-to-app ID sharing method bypasses typical privacy protections such as clearing cookies, Incognito Mode and Android's permission controls. Worse, it opens the door for potentially malicious apps eavesdropping on users’ web activity.