The KMS key policy includes wildcard (asterisk) principal. Make sure that KMS key policy excludes wildcard (asterisk) principal.
1Resources:
2  Resource:
3    Type: 'AWS::KMS::Key'
4    Properties:
5      EnableKeyRotation: true
6      KeyPolicy:
7        Version: 2012-10-17
8        Id: !Sub ${AWS::StackName}-${AWS::AccountId}-key-policy
9        Statement:
10          - Sid: Allow source account access to KMS key in source account
11            Effect: Allow
12            # Noncompliant: KMS key policy contains wildcard(*) principal.
13            Principal: '*'
14            Action: kms:*
15            Resource: '*'1Resources:
2  Resource:
3    Type: 'AWS::KMS::Key'
4    Properties:
5      EnableKeyRotation: true
6      KeyPolicy:
7        Version: 2012-10-17
8        Id: !Sub ${AWS::StackName}-${AWS::AccountId}-key-policy
9        Statement:
10          - Sid: Allow source account access to KMS key in source account
11            Effect: Allow
12            # Compliant: KMS key policy does not contain wildcard(*) principal.
13            Principal:
14              AWS: !Sub arn:aws:iam::${AWS::AccountId}:root
15            Action: kms:*
16            Resource: '*'