First thing testers are not responsible for fixing the bug they are only responsible for debugging the bug and prioritizing those bugs. These bugs are now reported in bug report template with the severity and priority of the bug. Tester assigns severity level to the defects depending upon their impact on other parts of application. Every bug has its severity and priority values assign by tester. If a defect does not allow you to go ahead and test the product, it is critical one so it has to be fixed as soon as possible. We have 5 levels as: