diff --git a/gunicorn/config.py b/gunicorn/config.py
index c8f8f16d..c36d0403 100644
--- a/gunicorn/config.py
+++ b/gunicorn/config.py
@@ -43,8 +43,8 @@ def make_settings(ignore=None):
 
 
 def auto_int(_, x):
-    if x.startswith('0') and not x.lower().startswith('0x'):
-        # for compatible with octal numbers in python3
+    # for compatible with octal numbers in python3
+    if re.match(r'0(\d)', x, re.IGNORECASE):
         x = x.replace('0', '0o', 1)
     return int(x, 0)
 
diff --git a/tests/test_config.py b/tests/test_config.py
index 28d470fa..714d2926 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -374,7 +374,9 @@ def test_reload(options, expected):
 
 
 @pytest.mark.parametrize("options, expected", [
-    (["--umask 0", "myapp:app"], 0),
+    (["--umask", "0", "myapp:app"], 0),
+    (["--umask", "0o0", "myapp:app"], 0),
+    (["--umask", "0x0", "myapp:app"], 0),
     (["--umask", "0xFF", "myapp:app"], 255),
     (["--umask", "0022", "myapp:app"], 18),
 ])