diff --git a/src/json-validator.cpp b/src/json-validator.cpp
index e10234f..96fa626 100644
--- a/src/json-validator.cpp
+++ b/src/json-validator.cpp
@@ -36,6 +36,8 @@ protected:
 	root_schema *root_;
 
 public:
+	virtual ~schema() = default;
+
 	schema(root_schema *root)
 	    : root_(root) {}