diff --git a/acme/setup.py b/acme/setup.py
index 9ee91676e..26ff4b7d7 100644
--- a/acme/setup.py
+++ b/acme/setup.py
@@ -8,7 +8,8 @@ version = '2.5.0.dev0'
 install_requires = [
     'cryptography>=2.5.0',
     'josepy>=1.13.0',
-    'PyOpenSSL>=17.5.0',
+    # pyOpenSSL 23.1.0 is a bad release: https://github.com/pyca/pyopenssl/issues/1199
+    'PyOpenSSL>=17.5.0,!=23.1.0',
     'pyrfc3339',
     'pytz>=2019.3',
     'requests>=2.20.0',
diff --git a/certbot-nginx/setup.py b/certbot-nginx/setup.py
index f349e9388..6a0da5b74 100644
--- a/certbot-nginx/setup.py
+++ b/certbot-nginx/setup.py
@@ -9,7 +9,8 @@ install_requires = [
     # https://github.com/certbot/certbot/issues/8761 for more info.
     f'acme>={version}',
     f'certbot>={version}',
-    'PyOpenSSL>=17.5.0',
+    # pyOpenSSL 23.1.0 is a bad release: https://github.com/pyca/pyopenssl/issues/1199
+    'PyOpenSSL>=17.5.0,!=23.1.0',
     'pyparsing>=2.2.1',
     'setuptools>=41.6.0',
 ]