This is a potential security issue, you are being redirected to https://csrc.nist.gov.
Hardware, firmware, and software elements of a trusted computing base implementing the reference monitor concept. Security kernel must mediate all accesses, be protected from modification, and be verifiable as correct.
NIST SP 800-53 Rev. 5 from CNSSI 4009-2015
NIST SP 800-53 Rev. 4 [Superseded] under Security Kernel from CNSSI 4009