diff --git a/setup.py b/setup.py
index 7bdd8e15..7e1f67d0 100644
--- a/setup.py
+++ b/setup.py
@@ -32,7 +32,7 @@
     # Newer versions require a Rust compiler to build, see
     # * https://github.com/openstack-charmers/zaza/issues/421
     # * https://mail.python.org/pipermail/cryptography-dev/2021-January/001003.html
-    'cryptography<3.4',
+    'cryptography<42.1',
 
     'hvac<0.7.0',
     'jinja2',