ΔE 12.1, fair: the same colour family, but not a straight swap. Fresh Rust is a little darker, more muted, warmer than Vermillion.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Fresh Rust is a little darker, more muted, warmer than Vermillion.
The same difference applies the other way round: Vermillion is a little lighter, more saturated, cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Vermillion on the colour wheel See Fresh Rust on the colour wheel
All matches: Vermillion equivalents · Fresh Rust equivalents