diff --git a/graphify/security.py b/graphify/security.py
index a2361171a..2c06a593a 100644
--- a/graphify/security.py
+++ b/graphify/security.py
@@ -115,6 +115,13 @@ def validate_url(url: str) -> str:
             f"Got: {url!r}"
         )
 
+    try:
+        port = parsed.port
+    except ValueError as exc:
+        raise ValueError(f"Blocked URL with an invalid port. Got: {url!r}") from exc
+    if port == 0:
+        raise ValueError(f"Blocked URL with port 0. Got: {url!r}")
+
     hostname = parsed.hostname
     if hostname:
         # Block known cloud metadata hostnames