An internal government memo written just days before the start of open enrollment for Obamacare warned of a "high" security risk because of a lack of testing of the HealthCare.gov website.

"Due to system readiness issues, the SCA (security control assessment) was only partly completed," said the internal memo from the Center for Medicare and Medicaid Services. "This constitutes a risk that must be accepted and mitigated to support the Marketplace Day 1 operations."