This is according to a post on Slashleaks by user DIMITRI12 where based on the listing, the OnePlus 6 will feature a 6.28-inch 2280×1080 display. It will also be powered by an octa-core processor clocked at 2.45GHz, 6GB of RAM, a 16MP front-facing camera, a 20+16MP rear-facing dual camera setup, 64GB of onboard storage, a 3,300mAh battery, and Android 8.1 Oreo preinstalled.
There is no mention of who will be the maker of the processor, but given that this is a flagship phone and OnePlus has worked with Qualcomm in the past for its previous phones, chances are we are looking at the use of the Qualcomm Snapdragon 845 which is more or less the default chipset for flagship handsets.
In any case we will have all the official details in the next couple of weeks, but in the meantime if the leaked photos and specs are to be believed, the OnePlus 6 is shaping up to be a pretty good handset.