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 'getcustomerdata' method relying on an unsigned 'ostripedata' cookie to determine Stripe product ownership for unauthenticated users. The 'checkpurchase' 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 'ostripedata' cookie with a target product ID, which is publicly exposed in the checkout block's HTML source.

The Otter Blocks – Gutenberg Blocks, Page Builder for Gutenberg Editor & FSE plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the contact form file field CSS metabox in all versions up to, and including, 2.6.3 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with contributor access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

The Otter Blocks – Gutenberg Blocks, Page Builder for Gutenberg Editor & FSE plugin for WordPress is vulnerable to Stored Cross-Site Scripting via REST API SVG File uploads in all versions up to, and including, 3.0.4 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with Author-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses the SVG file.

The Otter Blocks WordPress plugin before 2.6.6 does not properly escape its mainHeadings blocks' attribute before appending it to the final rendered block, allowing contributors to conduct Stored XSS attacks.