Light does not pass through a mirror, it reflects it. There is no dispersion involved in this process.
Work Step by Step
As discussed on page 728, chromatic aberrations in lenses occur because different colors of light travel at slightly different speeds within glass (this phenomenon is known as dispersion). Thus, the different colors are bent by different amounts. After multicolored light passes through the lens, the different colors will be focused at different positions, and the image appears blurry. A mirror doesn’t have these shortcomings because it reflects light off a smooth metallic surface, and there is no dispersion when it comes to reflection. All colors are reflected the same way.