The latest update the both the evasi0n jailbreak tool and its corresponding untether program fixes various security holes, as well as bugs for specific devices.
The latest version of the jailbreak tool is 1.4, and you can download it from the evasi0n website. If you have already jailbroken your device, you don’t need to re-run the tool. Instead, open Cydia and go to the “Changes” tab. Let Cydia refresh, and then upgrade the evasi0n untether package. The process will be complete after you reboot your device.
Be sure to update as quickly as possible, as it’s always best to stay as current as possible with this type of package.