diff --git a/docs/security.md b/docs/security.md
index 6d4a451c8..94b32b61f 100644
--- a/docs/security.md
+++ b/docs/security.md
@@ -48,6 +48,7 @@ Some keywords in JSON Schemas can lead to very slow validation for certain data.
 You can validate your JSON schemas against [this meta-schema](../lib/refs/json-schema-secure.json) to check that these recommendations are followed:
 
 ```javascript
+ajv = new Ajv({strictTypes: false}) // this option is required for this schema
 const isSchemaSecure = ajv.compile(require("ajv/lib/refs/json-schema-secure.json"))
 
 const schema1 = {format: "email"}