diff --git a/pyvulnerabilitylookup/api.py b/pyvulnerabilitylookup/api.py
index ab7e00f..2897865 100644
--- a/pyvulnerabilitylookup/api.py
+++ b/pyvulnerabilitylookup/api.py
@@ -204,7 +204,7 @@ def get_vendor_product_vulnerabilities(self, vendor: str, product: str,
         return r.json()
 
     def get_vendor_product_vulnerabilities_iter(self, vendor: str, product: str,
-                                                *, since: date | datetime) -> Generator[dict[str, Any]]:
+                                                *, since: date | datetime | None=None) -> Generator[dict[str, Any]]:
         '''Iterate over the vulnerabilities per vendor and a specific product
 
         :param vendor: A vendor owning products (must be in the known vendor list)
@@ -215,12 +215,14 @@ def get_vendor_product_vulnerabilities_iter(self, vendor: str, product: str,
         per_page = 10
         while True:
             r = self.get_vendor_product_vulnerabilities(vendor, product, since=since, page=page, per_page=per_page)
-            # The format i the response is a dict with the source as key,
+            # The format in the response is a dict with the source as key,
             # that contains a list [[ID, vulnerability], ...]
-            # we yield that last part
+            # we yield that last part appended with the source as a third element.
             if not any(r.values()):
                 break
-            for vulnerabilities in r.values():
+            for origin, vulnerabilities in r.items():
+                for vulnerability in vulnerabilities:
+                    vulnerability.append(origin)
                 yield from vulnerabilities
             page += 1