diff --git a/changelogs/fragments/1005-openssl-4.yml b/changelogs/fragments/1005-openssl-4.yml
new file mode 100644
index 00000000..347e4a06
--- /dev/null
+++ b/changelogs/fragments/1005-openssl-4.yml
@@ -0,0 +1,2 @@
+bugfixes:
+  - "acme_* modules - adjust OpenSSL RSA private key output parsing to OpenSSL 4.0.0 (https://github.com/ansible-collections/community.crypto/pull/1005)."
diff --git a/plugins/module_utils/acme/backend_openssl_cli.py b/plugins/module_utils/acme/backend_openssl_cli.py
index ae9238e5..6ec6b831 100644
--- a/plugins/module_utils/acme/backend_openssl_cli.py
+++ b/plugins/module_utils/acme/backend_openssl_cli.py
@@ -164,7 +164,7 @@ class OpenSSLCLIBackend(CryptoBackend):
 
         if account_key_type == "rsa":
             pub_hex = re.search(
-                r"modulus:\n\s+00:([a-f0-9\:\s]+?)\npublicExponent",
+                r"modulus:\n\s+(?:00:)?([a-f0-9\:\s]+?)\npublicExponent",
                 out_text,
                 re.MULTILINE | re.DOTALL,
             ).group(1)