ΔE 18.4, loose: different enough that you should pick on purpose. Earth Brown is noticeably darker, more saturated than Combat Fatigues.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Earth Brown is noticeably darker, more saturated than Combat Fatigues.
The same difference applies the other way round: Combat Fatigues is noticeably lighter, more muted.
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 Combat Fatigues on the colour wheel See Earth Brown on the colour wheel
All matches: Combat Fatigues equivalents · Earth Brown equivalents