The sudden release of the iOS 8 jailbreak tool by the Pangu team was a bit of a surprise, even for Saurik himself, who was reported to be working on an update for cydia to be iOS 8 compatible. The good news is that he’s already achieved that, but it has to be manually installed using a .deb file for installing Cydia. If you’re as impatient as me and want it now, it is available on his website, for which the direct link to download is here. But, make sure to backup your device as it could lead to a bootloop. Now, if you’re wondering how to install the deb file manually without Cydia or iFile, all you have to do is use iExplorer or iFunbox from your computer to install the deb file to your iPhone
However, it is recommended to wait for a further more stable and proper update. Also before you attempt to use the Pangu tool, it is always better to perform a restore on your device. Also keep in mind that a lot of tweaks might not work with iOS 8, and some might work just partially with bugs. So, be cautious while using this jailbreak for a few days, as it has been just released and is expected to have a few bugs.
To download the Pangu tool head over to their website pangu.io .