The Windows Server 2025 "Modify firmware environment values" user right must only be assigned to the Administrators group.
Inappropriately granting user rights provides system, administrative, and other high-level capabilities.
Accounts with the "Modify firmware environment values" user right can change hardware configuration environment variables. This could result in hardware failures or a denial of service.
How this relates to the STIG checklist: STIG vs SCAP benchmark.