X0206 3 2022-10-12 0 0001877939 Castellum, Inc. CTM 0001946870 Buckhout Laurie M 3 BETHESDA METRO CENTER, SUITE 700 BETHESDA MD 20814 1 1 0 0 Chief Revenue Officer Convertible Promissory Note 0.26 Common Stock I See footnote The Buckhout Charitable Remainder Trust , Laurie Buckhout, TTEE is the holder of a convertible promissory note in the principal amount of $3,709,617 which has a maturity date of September 30, 2024 and is convertible into Common Stock at $0.26 per share. At the closing of the Company's offering it is expected that $1,000,000 of the principal amount then outstanding will be converted into 3,846,154 shares of Common Stock at $0.26 per share. /s/ Laurie Buckhout 2022-10-12