GraphQL Playground is a GraphQL IDE for development of graphQL focused applications. All versions of graphql-playground-react older than graphql-playground-react@1.7.28 are vulnerable to compromised HTTP schema introspection responses or schema prop values with malicious GraphQL type names, exposing a dynamic XSS attack surface that can allow code injection on operation autocomplete. In order for the attack to take place, the user must load a malicious schema in graphql-playground. There are several ways this can occur, including by specifying the URL to a malicious schema in the endpoint query parameter. If a user clicks on a link to a GraphQL Playground installation that specifies a malicious server, arbitrary JavaScript can run in the user's browser, which can be used to exfiltrate user credentials or other harmful goals. If you are using graphql-playground-react directly in your client app, upgrade to version 1.7.28 or later.

Affected: npm: graphql-playground-react

## GraphQL Playground introspection schema template injection attack: Advisory Statement

This is a security advisory for an XSS vulnerability in `graphql-playground`.

A similar vulnerability affects `graphiql`, the package from which `graphql-playground` was forked. There is a corresponding `graphiql` [advisory](https://github.com/graphql/graphiql/security/advisories/GHSA-x4r7-m2q9-69c8).

- [1. Impact](#1-impact) - [2. Scope](#2-scope) - [3. Patches](#3-patches) - [4. Reproducing the exploit](#4-reproducing-the-exploit) - [5. Credit](#5-credit) - [6. For more information](#6-for-more-information)

### 1. Impact

All versions of `graphql-playground-react` older than `graphql-playground-react@1.7.28` are vulnerable to compromised HTTP schema introspection responses or `schema` prop values with malicious GraphQL type names, exposing a dynamic XSS attack surface that can allow code injection on operation autocomplete.

In order for the attack to take place, the user must load a malicious schema in `graphql-playground`. There are several ways this can occur, including by specifying the URL to a malicious schema in the `endpoint` query parameter. If a user clicks on a link to a GraphQL Playground installation that specifies a malicious server, arbitrary JavaScript can run in the user's browser, which can be used to exfiltrate user credentials or other harmful goals.

### 2. Scope

This advisory describes the impact on the `graphql-playground-react` package. The vulnerability al…