diff --git a/server.py b/server.py
index 255369cbea27081d4bc31208a6fa094ebcbec927..ae873a0c0fbc02e14e81b5da8d4293e145f668c3 100644
--- a/server.py
+++ b/server.py
@@ -94,7 +94,7 @@ def csrf_protect(func):
 
 @app.url_defaults
 def csrf_inject(endpoint, values):
-	if endpoint not in csrf_endpoints or not session['_csrf_token']:
+	if endpoint not in csrf_endpoints or not session.get('_csrf_token'):
 		return
 	values['_csrf_token'] = session['_csrf_token']