Winter CMS: CSRF through AJAX handler names reachable as backend page actions

Winter CMS is a content management system built on the Laravel PHP framework. From 1.0.319 until 1.2.14, Backend\Classes\Controller::actionExists() accepts public handler-shaped methods as page actions, so a top-level GET request can invoke state-changing backend AJAX handlers without a CSRF token. Because backend routes use Route::any, CSRF validation skips GET, and the default SameSite=Lax session cookie is sent on cross-site navigation, an unauthenticated attacker can induce an authorized backend user to follow a link such as /backend/system/eventlogs/index_onEmptyLog. Affected handlers in the backend, CMS, and system modules can truncate logs, reset settings, alter backend user state, or delete CMS templates, while URL path segments can select a target record. This issue is fixed in version 1.2.14.