Decidim is a participatory democracy framework. Starting in version 0.23.0 and prior to versions 0.27.5 and 0.28.0, the CSRF authenticity token check is disabled for the questionnaire templates preview. The issue does not imply a serious security thread as you need to have access also to the session cookie in order to see this resource. This URL does not allow modifying the resource but it may allow attackers to gain access to information which was not meant to be public. The issue is fixed in version 0.27.5 and 0.28.0. As a workaround, disable the templates functionality or remove all available templates.
github.com/decidim/decidim/blob/3187bdfd40ea1c57c2c12512b09a7fec0b2bed08/decidim-templates/app/controllers/decidim/templates/admin/questionnaire_templates_controller.rb
github.com/decidim/decidim/commit/5542227be66e3b6d7530f5b536069bce09376660
github.com/decidim/decidim/commit/57a4b467787448307b5d9b01ce6e2c8502e121ac
github.com/decidim/decidim/pull/11743
github.com/decidim/decidim/pull/6247
github.com/decidim/decidim/releases/tag/v0.27.5
github.com/decidim/decidim/releases/tag/v0.28.0
github.com/decidim/decidim/security/advisories/GHSA-f3qm-vfc3-jg6v