FuncTion-V is a tool for the automatic identification of the minimal sets of program variables that an attacker can control to ensure an undesirable program property. FuncTion-V supports program properties expressed in Computation Tree Logic (CTL), and builds upon an abstract interpretation-based static analysis for CTL properties that we extend with an abstraction refinement process. FuncTion-V was developed to implement and test the analysis method and abstract domains described in the paper Automatic Detection of Vulnerable Variables for CTL Properties of Program by Naïm Moussaoui Remil, Caterina Urban, and Antoine Miné at LPAR 2024.