diff --git a/Lib/ipaddress.py b/Lib/ipaddress.py
index 160b16d..af7aedf 100644
--- a/Lib/ipaddress.py
+++ b/Lib/ipaddress.py
@@ -1223,6 +1223,11 @@ def _parse_octet(cls, octet_str):
         if len(octet_str) > 3:
             msg = "At most 3 characters permitted in %r"
             raise ValueError(msg % octet_str)
+        # Handle leading zeros as strict as glibc's inet_pton()
+        # See security bug bpo-36384
+        if octet_str != '0' and octet_str[0] == '0':
+            msg = "Leading zeros are not permitted in %r"
+            raise ValueError(msg % octet_str)
         # Convert to integer (we know digits are legal)
         octet_int = int(octet_str, 10)
         if octet_int > 255: