diff --git a/docs/dfx-json-schema.json b/docs/dfx-json-schema.json
index 519590876c..6c47fb057d 100644
--- a/docs/dfx-json-schema.json
+++ b/docs/dfx-json-schema.json
@@ -567,7 +567,8 @@
             }
           ]
         }
-      }
+      },
+      "additionalProperties": false
     },
     "ConfigCanistersCanisterRemote": {
       "title": "Remote Canister Configuration",
diff --git a/src/dfx-core/src/config/model/dfinity.rs b/src/dfx-core/src/config/model/dfinity.rs
index cc62cc2861..774cda5af9 100644
--- a/src/dfx-core/src/config/model/dfinity.rs
+++ b/src/dfx-core/src/config/model/dfinity.rs
@@ -241,6 +241,7 @@ pub const DEFAULT_REPLICA_PORT: u16 = 8080;
 /// # Canister Configuration
 /// Configurations for a single canister.
 #[derive(Clone, Debug, Serialize, Deserialize, JsonSchema)]
+#[schemars(deny_unknown_fields)]
 pub struct ConfigCanistersCanister {
     /// # Declarations Configuration
     /// Defines which canister interface declarations to generate,