Duztas, Koray2025-09-152025-09-1520252190-544410.1140/epjp/s13360-025-06743-w2-s2.0-105013634649https://doi.org/10.1140/epjp/s13360-025-06743-whttps://hdl.handle.net/20.500.14517/8350Previous attempts to overspin or overcharge Kerr-Sen black holes have been incomplete, as they neglect back-reaction effects. In this study, we incorporate the self-energy of perturbations, resulting from the induced increase in the angular velocity and the electrostatic potential of the event horizon, as described in a seminal work by Will. Our analysis demonstrates that Kerr-Sen black holes cannot be overspun or overcharged by perturbations that satisfy the null energy condition, within a comprehensive second-order framework that includes the self-energy of the perturbations.eninfo:eu-repo/semantics/closedAccessArticleQ2Q21408WOS:001553817700001