Mozilla is expected to release a security patch in the near future for Firefox, whose vulnerability is apparently exploited to attack Tor users.
These two browsers often share similar vulnerabilities. And that’s why Mozilla is scrambling to track the bug and come up with a patch to address the concern.
What’s interesting is that the code that is being used to unmask identities of Tor users is extremely similar to the one used by the FBI in the past in tracking down dark-web child-abuse website users. However, given the fact that the latest exploit sends a unique identifier to a French address, and not directly to the agency, it is unlikely the FBI is involved in it.
Window users out there: if the potential exploit bothers you, your best bet would be Chrome or Edge, which should be more difficult to exploit due to memory partitioning.