How insecure is your phone that someone can digitally compromise you without knowing the passcode? If you lock a modern iPhone, even the FBI will have trouble extracting any content from it.
And those are publicly known capabilities. You should assume that potential adversaries will have more than that. Am I certain that such exploits are known for the very most recent iPhone/iOS? No. But it would still be foolish to bet on them not being known.
Cheers.