:- A software product spends more than 65% of its lifecycle in maintenance. Software systems with good maintainability can be easily modified to fix faults. In this paper, we adapt our methodology for assessing maintainability-based risk into the context of corrective maintenance. The methodology depends on the architectural artifacts and their evolution through the life cycle of the system. In order to prioritize corrective maintenance tasks, we combine component maintainability – based risk with the severity of a failure that may happen as a result of unfixed fault. We illustrate the methodology on a case study using UML models.