Strengthening Mosquito Abatement for Safety and Health Act or the SMASH Act This bill amends the Public Health Service Act to revise and extend through FY2023 Centers for Disease Control and Prevention (CDC) grants for mosquito control programs. The grant program is expanded so that grants may be used to address emerging, infectious mosquito-borne diseases and to improve existing control programs. The CDC must give preference to applicants that have: (1) a public health emergency due to a mosquito-borne disease, or (2) a control program that is consistent with existing state preparedness plans. The requirement for matching funds may be waived if the area covered by a grant applicant has an extreme need due to the size or density of the human population, the size or density of the mosquito population, or the severity of the mosquito-borne disease. CDC grants to help public health agencies improve surveillance and response activities are extended through FY2023. The Government Accountability Office must report on the surveillance and control of mosquito-borne infectious diseases in the United States and territories.