Update: According to @drscjmm this will not work when a passcode is set, which means we are still in pretty good shape from a security standpoint.
Untethered, which means you still need to plug the device into a computer, but the jailbreak lasts across reboots (this is not remotely executable at this time).
This means all iOS devices are exposed to hands-on forensics, even with a passcode. Data protection still needs to be broken, but an attacker can jailbreak and install a back door to sniff your password if they have physical control of the device for long enough. if you lose your phone and recover it, wipe it and restore from a known unjailbroken backup.
From the jailbreak notes:
Please disable the lock passcode of your iOS device before using evasi0n. It can cause issues.
I can’t test right now, but will be interesting if a passcode prevents the jailbreak, or is sometimes just an obstacle. Please leave comments if you know or find out.
Update: As we said above, a passcode appears to block this jailbreak, which is good.
(Hat tip to The Verge for the link).