diff --git a/operatingsystems/managers.py b/operatingsystems/managers.py
index 630484a1..b7b9f24f 100644
--- a/operatingsystems/managers.py
+++ b/operatingsystems/managers.py
@@ -18,5 +18,5 @@
 
 
 class OSReleaseManager(models.Manager):
-    def get_by_natural_key(self, name, codename):
-        return self.get(name=name, codename=codename)
+    def get_by_natural_key(self, name, codename, cpe_name):
+        return self.get(name=name, codename=codename, cpe_name=cpe_name)
diff --git a/security/models.py b/security/models.py
index 0f848260..405c8db6 100644
--- a/security/models.py
+++ b/security/models.py
@@ -125,6 +125,8 @@ def add_cvss_score(self, vector_string, score=None, severity=None, version=None)
             score = cvss_score.base_score
         if not severity:
             severity = cvss_score.severities()[0]
+        if isinstance(severity, str):
+            severity = severity.capitalize()
         try:
             cvss, created = CVSS.objects.get_or_create(
                 version=version,