The Bugs Framework (BF) is a set of software weakness classes. Each BF class comprises (1) an accurate and precise definition, (2) attributes that identify the software fault, (3) possible causes, (4) consequences that it could lead to, and (5) code sites where it might occur. Building on CWEs, Software Fault Patterns, and Semantic Templates, the Bugs Framework allows us to precisely and unambiguously express software bugs.