The vulnerability is an insecure direct object reference in the Otter Blocks WordPress plugin that allows an attacker to manipulate the product_id parameter separately from the price_id in the Stripe checkout URL. Because the plugin’s watch_checkout function does not validate that these keys match, an unauthenticated user can pay a lower price while receiving entitlement to a higher‑tier product. This results in unauthorized access to premium features and potential financial loss for the site owner.

WordPress sites that install the themeisle Otter Blocks – Gutenberg Blocks, Page Builder for Gutenberg Editor & FSE plugin, in any version up to and including 3.1.7. The plugin’s checkout handling is affected across all installations using the vulnerable code base.

The CVSS score of 5.3 indicates moderate severity, and the EPSS score is not available. The vulnerability is not listed in the CISA KEV catalog. Because the bug allows unauthenticated manipulation of payment parameters through a publicly reachable endpoint, it can be exploited by any user with internet access to a site running the plugin. The lack of input validation on product identifiers creates an authorization bypass that can be used by attackers to obtain premium entitlements without proper payment, leading to both financial loss and unauthorized content access.