Explicitly add `protect_from_forgery` action

Otherwise the token might be cleared before authentication is
done, causing the authentication itself to fail

app/controllers/sessions_controller.rb

@@ -5,6 +5,14 @@ class SessionsController < Devise::SessionsController
 
   skip_before_action :check_two_factor_requirement, only: [:destroy]
 
+  # Explicitly call protect from forgery before anything else. Otherwise the
+  # CSFR-token might be cleared before authentication is done. This was the case
+  # when LDAP was enabled and the `OmniauthCallbacksController` is loaded
+  #
+  # *Note:* `prepend: true` is the default for rails4, but this will be changed
+  # to `prepend: false` in rails5.
+  protect_from_forgery prepend: true, with: :exception
+
   prepend_before_action :check_initial_setup, only: [:new]
   prepend_before_action :authenticate_with_two_factor,
     if: :two_factor_enabled?, only: [:create]

changelogs/unreleased/bvl-fix-login-issue-with-ldap-enabled.yml

+---
+title: Fix cross site request protection when logging in as a regular user when LDAP
+  is enabled
+merge_request: 13049
+author: