diff --git a/pkgs/development/python-modules/pysaml2/default.nix b/pkgs/development/python-modules/pysaml2/default.nix
index 188bf2e3f80e..53eac4e8caad 100644
--- a/pkgs/development/python-modules/pysaml2/default.nix
+++ b/pkgs/development/python-modules/pysaml2/default.nix
@@ -98,6 +98,8 @@ buildPythonPackage rec {
   pythonImportsCheck = [ "saml2" ];
 
   meta = with lib; {
+    # https://github.com/IdentityPython/pysaml2/issues/947
+    broken = lib.versionAtLeast xmlschema.version "4.2.0";
     description = "Python implementation of SAML Version 2 Standard";
     homepage = "https://github.com/IdentityPython/pysaml2";
     changelog = "https://github.com/IdentityPython/pysaml2/blob/v${version}/CHANGELOG.md";