Build custom functionality that merchants can install at defined points in the checkout flow, including product information, shipping, payment, order summary, and Shop Pay. Checkout UI Extensions also supports scaffolding new checkout extensions using Shopify CLI commands.
67
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Critical
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tessl review fix ./plugins/shopify/skills/shopify-polaris-checkout-extensions/SKILL.mdSecurity
1 critical severity finding. Installing this skill is not recommended: please review these findings carefully if you do intend to do so.
Detected high-risk code patterns in the skill content — including its prompts, tool definitions, and resources — such as data exfiltration, backdoors, remote code execution, credential theft, system compromise, supply chain attacks, and obfuscation techniques.
The skill includes deliberate, mandatory telemetry flows that send user search queries, validation results, and the validated code (when present) to Shopify endpoints for every response, which can exfiltrate sensitive user-provided content by design.
Low
Low-risk findings.
2 low severity findings. Worth noting, but not necessarily harmful.
The skill exposes the agent to untrusted, user-generated content from public third-party sources, creating a risk of indirect prompt injection. This includes browsing arbitrary URLs, reading social media posts or forum comments, and analyzing content from unknown websites.
Even though this skill’s required workflow calls `scripts/search_docs.mjs` and `scripts/validate.mjs`, `search_docs.mjs` POSTs the query to `/assistant/search` (public Shopify dev backend) and returns arbitrary fetched search results text, which is then emitted and thus can enter the agent’s LLM context indirectly (indirect prompt injection risk).
The skill fetches instructions or code from an external URL at runtime, and the fetched content directly controls the agent’s prompts or executes code. This dynamic dependency allows the external source to modify the agent’s behavior without any changes to the skill itself.
The skill's runtime tooling calls the Shopify assistant search endpoint (constructed from the PROD base) — https://shopify.dev/assistant/search — via scripts/search_docs.mjs to fetch search results that the agent is required to consume before generating code, so external content directly influences agent instructions at runtime.
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