Decoded neurofeedback is a new technology that allows the improvement or modification of human cognitive and moral capacities and has a wide range of potential applications. As decoded neurofeedback will have an impact on society, ethical concerns about this technology should be examined. As decoded neurofeedback modifies the default mode network due to a voxel-based pattern analysis, it enables a tailor-made intervention. However, it is difficult to assess the safety and efficacy of decoded neurofeedback-based interventions in clinical trials because of a shortage of reliable preclinical data. Decoded neurofeedback used for moral enhancement is a noninvasive intervention with a high selectivity for the targeted brain state, and therefore, moral uniformity, the most often discussed problem, can be avoided. However, it remains uncertain whether decoded neurofeedback is reversible, safe, or efficacious.