There’s a problem with the implementation of the IndexedDB API in Safari’s WebKit engine, which could result in leaking browsing activity in real-time and even user identities to anyone exploiting this flaw. IndexedDB is a widely used browser API that is a versatile client-side storage system with no capacity limits.
While this is unfortunate there is a simple answer that would avoid this and future problems not just on your Apple devices, but others as well (since this bug affects more than just Apple Users).
Link: Safari bug leaks your Google account info, browsing history
via www.bleepingcomputer.com