1 files changed, 8 insertions, 2 deletions
diff --git a/ext/json/json.c b/ext/json/json.c
index ddfbbe5d26..90e5955c09 100644
--- a/ext/json/json.c
+++ b/ext/json/json.c
@@ -269,8 +269,14 @@ static void json_escape_string(smart_str *buf, char *s, int len, int options) /*
         {
             efree(utf16);
         }
-
-        smart_str_appendl(buf, "\"\"", 2);
+		if(len < 0) {
+			if(!PG(display_errors)) {
+				php_error_docref(NULL TSRMLS_CC, E_WARNING, "Invalid UTF-8 sequence in argument");
+			}
+	        smart_str_appendl(buf, "null", 4);
+		} else {
+	        smart_str_appendl(buf, "\"\"", 2);
+		}
         return;
     }