diff --git a/pkgs/development/python-modules/untangle/default.nix b/pkgs/development/python-modules/untangle/default.nix
index 820c96c38c90..6582f5080bd0 100644
--- a/pkgs/development/python-modules/untangle/default.nix
+++ b/pkgs/development/python-modules/untangle/default.nix
@@ -1,17 +1,21 @@
-{ lib, buildPythonPackage, fetchFromGitHub, python }:
+{ lib, buildPythonPackage, fetchFromGitHub, python, defusedxml }:
 
 buildPythonPackage rec {
   pname = "untangle";
-  version = "1.1.1";
+  version = "1.2.1";
 
   src = fetchFromGitHub {
     owner = "stchris";
     repo = "untangle";
     # 1.1.1 is not tagged on GitHub
-    rev = "61b57cd771a40df7d1621e9ec3c68d9acd733d31";
-    sha256 = "0ffvlfyyl82xi4akz1lls32lrnlrn44ik41v8x8xh9ghy0n0ick7";
+    rev = "refs/tags/${version}";
+    sha256 = "sha256-cJkN8vT5hW5hRuLxr/6udwMO4GVH1pJhAc6qmPO2EEI=";
   };
 
+  propagatedBuildInputs = [
+    defusedxml
+  ];
+
   checkPhase = ''
     ${python.interpreter} -m unittest discover -s tests
   '';