Defect Severity and Priority TypesIn Software Testing, Defect severity can be categorized into four classCritical: This defect indicates complete shut-down of the process, nothing can proceed furtherMajor: It is a highly severe defect and collapses the system. However, certain parts of the system remain functionalMedium: It causes some undesirable behavior, but the system is still functionalLow: It won't cause any major break-down of the systemDefect priority can be categorized into three classLow: The Defect is an irritant but repair can be done once the more serious Defect has been fixedMedium: During the normal course of the development activities defect should be resolved. It can wait until a new version is createdHigh: The defect must be resolved as soon as possible as it affects the system severely and cannot be used until it is fixed