alexw91

Just trying to think if there are any other potential immediate recommendations for non-technical friends and family with Android phones from these vendors other than "don't sideload any apps" and "make sure to install any security updates as soon as they're available".

That's not how the TLS handshake works. The TLS server must be configured to request a certificate from the client in order for the client to know that it needs to send a client certificate to the server, and that server-side configuration is disabled for ~99%+ of endpoints.

TLS server implementations should be aborting the TLS connection for violating the TLS Handshake state machine if a client attempts to send a client certificate when it wasn't requested.

So while this bug affects both clients and servers, 100% of clients are parsing the server's TLS cert during the TLS handshake, but less than ~1% of servers are parsing a client's certificate during a handshake.

It's theoretically possible for someone to record encrypted traffic today, keep a copy of it for a decade or two until quantum computers are available, and then decrypt it in the future using the quantum computer. If you have data today, that needs to be secure for more than a few decades, you may want to move to post quantum crypto soon to stop that potential leak.