diff --git a/src/printer_json.c b/src/printer_json.c
index 165dfab5d..312e30df1 100644
--- a/src/printer_json.c
+++ b/src/printer_json.c
@@ -363,7 +363,8 @@ json_print_value(struct jsonpr_ctx *pctx, const struct ly_ctx *ctx, const struct
     switch (basetype) {
     case LY_TYPE_UNION:
         /* use the resolved type */
-        basetype = val->subvalue->value.realtype->basetype;
+        val = &val->subvalue->value;
+        basetype = val->realtype->basetype;
         goto print_val;
 
     case LY_TYPE_BINARY: