Scrum in dynamic environments

How to implement scrum in highly dynamic environments?

Consider a scenario where you want to implement scrum in a project which involve fixing unknown defects in the product. Some of these defects are show stoppers hence cannot wait. Some others are of high priority and some with low priority. In such scenarios there is no room for sprint planning meeting.

In such scenarios, run a running scrum (kanban) with daily scrum meetings, reviews and retrospectives.