Concrete CMS does not validate a CSRF token before processing requests to `/dashboard/extend/update/prepare_remote_upgrade/<remoteMPID>`

Concrete CMS 9.5.0 and below does not validate a CSRF token before processing requests to /dashboard/extend/update/prepareremoteupgrade/. An attacker who controls the remote package returned for a known marketplace item ID can overwrite the package PHP on disk and force its upgrade method to...