diff --git a/app/controllers/programming_groups_controller.rb b/app/controllers/programming_groups_controller.rb
index 78494a99..d89642e7 100644
--- a/app/controllers/programming_groups_controller.rb
+++ b/app/controllers/programming_groups_controller.rb
@@ -94,6 +94,8 @@ class ProgrammingGroupsController < ApplicationController
   private
 
   def authorize!
+    raise Pundit::NotAuthorizedError if @programming_group.present? && @exercise.present? && @programming_group.exercise != @exercise
+
     authorize(@programming_group || @programming_groups)
   end