diff --git a/cJSON.c b/cJSON.c
index 4b5005a4519a368857ac98bbaff719c684b65930..89943b5d0c03eace64c409b8f79839033bd34d70 100644
--- a/cJSON.c
+++ b/cJSON.c
@@ -300,7 +300,7 @@ static unsigned char* ensure(printbuffer *p, size_t needed)
         }
         if (newbuffer)
         {
-            memcpy(newbuffer, p->buffer, p->length);
+            memcpy(newbuffer, p->buffer, p->offset + 1);
         }
         cJSON_free(p->buffer);
     }