FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.214, the undo-send route GET /conversation/undo-reply/{thread_id} checks only whether the current user can view the parent conversation. It does not verify that the current user created the reply being undone. In a shared mailbox, one agent can therefore recall another agent's just-sent reply during the 15-second undo window. Version 1.8.214 fixes the vulnerability.