Cart Abandonment Recovery for WooCommerce < 2.2.0 - Unauthenticated Authentication Bypass via Unsigned Recovery Token

Description

The plugin does not verify the integrity of its cart-recovery token before acting on it and still accepts an unsigned legacy token format, allowing unauthenticated attackers who know a victim's cart session identifier to modify that victim's abandoned-cart record, for example unsubscribing them from recovery emails or applying an arbitrary coupon to their restored cart.