The CFP for BSides Ume this summer (starting June 27th!) ends in two work weeks from now!
https://indico.neic.no/event/244/
The abstract submission involves a quick e-mail verified lightweight account in the conference management system to track contributions (later, speakers will be able to upload materials into the timetable etc), but that also means that you can update a submitted abstract all the way to the deadline. I recommend you submit early and update often!