silverstripeCMS Incorrect Default Permissions Vulnerability (CVE-2020-6165)

Description

SilverStripe 4.5.0 allows attackers to read certain records that should not have been placed into a result set. This affects silverstripe/recipe-cms. The automatic permission-checking mechanism in the silverstripe/graphql module does not provide complete protection against lists that are limited (e.g., through pagination), resulting in records that should have failed a permission check being added to the final result set. GraphQL endpoints are configured by default (e.g., for assets), but the admin/graphql endpoint is access protected by default. This limits the vulnerability to all authenticated users, including those with limited permissions (e.g., where viewing records exposed through admin/graphql requires administrator permissions). However, if custom GraphQL endpoints have been configured for a specific implementation (usually under /graphql), this vulnerability could also be exploited through unauthenticated requests. This vulnerability only applies to reading records; it does not allow unauthorised changing of records.