Special relativity does not forbid all faster-than-light travel. It only forbids faster-than-light travel for particles with mass that start out traveling under the speed of light.
This is because the equations of special relativity indicate it would take an infinite amount of energy to accelerate a particle with mass through the speed of light. However, if a particle with mass is created with an initial velocity greater than the speed of light, that is not a problem. Indeed, scientists even have a name for such a particle – the tachyon
. The particle is hypothetical, of course, but it is consistent with special relativity.