Mo. Rev. Stat. § 434.010: Bonds, notes founded on gaming considerations, void.

All judgments by confession, conveyances, bonds, bills, notes and securities, when the consideration is money or property won at any game, gambling device, or by any bet or wager whatever, shall be void and may be set aside and vacated by any court of competent jurisdiction, upon suit brought for that purpose by the person so confessing, giving, entering into or executing the same, or by his executors or administrators or by any creditor, heir, devisee, purchaser or other person interested therein.