The Otter Blocks plugin for WordPress is vulnerable to Purchase Verification Bypass in all versions up to, and including, 3.1.4. This is due to the 'get_customer_data' method relying on an unsigned 'o_stripe_data' cookie to determine Stripe product ownership for unauthenticated users. The 'check_purchase' method trusts this cookie data without performing server-side verification against the Stripe API for one-time 'payment' mode purchases. This makes it possible for unauthenticated attackers to bypass Stripe purchase-gated content visibility conditions by forging the 'o_stripe_data' cookie with a target product ID, which is publicly exposed in the checkout block's HTML source.