Otter Blocks < 3.1.5 - Unauthenticated Purchase Verification Bypass via Forged Cookie

Description

The plugin is vulnerable to Purchase Verification Bypass 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.