diff --git a/lib/plugins/aws/provider.js b/lib/plugins/aws/provider.js
index 723d88dad20..7af79fce0a4 100644
--- a/lib/plugins/aws/provider.js
+++ b/lib/plugins/aws/provider.js
@@ -338,6 +338,8 @@ class AwsProvider {
               { $ref: '#/definitions/awsCfGetAtt' },
               { $ref: '#/definitions/awsCfRef' },
               { $ref: '#/definitions/awsCfSub' },
+              { $ref: '#/definitions/awsCfBase64' },
+              { $ref: '#/definitions/awsCfToJsonString' },
             ],
           },
           awsCfGetAtt: {
@@ -480,6 +482,12 @@ class AwsProvider {
             required: ['Fn::Sub'],
             additionalProperties: false,
           },
+          awsCfBase64: {
+            type: 'object',
+            properties: {
+              'Fn::Base64': {},
+            },
+          },
           awsCfToJsonString: {
             type: 'object',
             properties: {
@@ -577,7 +585,6 @@ class AwsProvider {
                   { $ref: '#/definitions/awsCfInstruction' },
                   { $ref: '#/definitions/awsCfIf' },
                   { $ref: '#/definitions/awsCfSelect' },
-                  { $ref: '#/definitions/awsCfToJsonString' },
                 ],
               },
             },