diff --git a/ql/test/query-tests/Security/CWE-079/tst.go b/ql/test/query-tests/Security/CWE-079/tst.go
index 76bb3d8fe4c..dfdf3bbf6b0 100644
--- a/ql/test/query-tests/Security/CWE-079/tst.go
+++ b/ql/test/query-tests/Security/CWE-079/tst.go
@@ -65,7 +65,7 @@ func serve9(log io.Writer) {
 		r.ParseForm()
 		username := r.Form.Get("username")
 		// OK: not a ResponseWriter
-		log.Write(username)
+		log.Write([]byte(username))
 	})
 	http.ListenAndServe(":80", nil)
 }