7 CFR §3565.502

In the case of loans that back Ginnie Mae securities or loans that are acquired by Ginnie Mae as a consequence of its guaranty, the Agency guarantee under this part is incontestable except that the guarantee may not be enforced by a lender who commits fraud or misrepresentation or by a lender who had knowledge of the fraud or misrepresentation at the time such a lender acquired the guarantee or was assigned the loan.