2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/228137Metrics representing black holes in General Relativity may exhibit naked singularities for certain values of their parameters. This is the case for super-extremal ($J^2 > M>0$) Kerr and super-extremal ($|Q|>M>0$) Reissner-Nördstrom spacetimes, and also for the negative mass Schwarzschild spacetime. We review our recent work where we show that these nakedly singular spacetimes are unstable under linear gravitational perturbations, a result that supports the cosmic censorship conjecture, and also that the inner stationary region beyond the inner horizon of a Kerr black hole ($J^2 <M$) is linearly unstable.Review talk given at the 7th Friedmann Seminar, Joao Pessoa, Brazil, July 2008General Relativity and Quantum Cosmologytext