The Vacancy to Value Act of 2026 directs the General Services Administration to create a five-year pilot program that allows the sale or transfer of underutilized federal properties to eligible buyers at potentially below fair market value for community development purposes like affordable housing, job creation, and community facilities. Buyers acquiring property under this program must submit redevelopment plans and begin work within five years, with priority given to nonprofit organizations and public entities. The bill also establishes a separate Federal Redevelopment Grant Program administered by the Department of Housing and Urban Development to provide competitive grants to eligible entities including local governments, nonprofits, tribal governments, and public housing agencies for activities such as site preparation, construction, and infrastructure improvements on redeveloped properties. Grant recipients must demonstrate that their projects will benefit low-income or historically underserved communities and must provide annual progress reports to the Secretary of HUD. The legislation authorizes unspecified funding levels for the grant program and requires a study and congressional report on pilot program outcomes within 12 months of the program's termination.