GraphQL-Ruby is a widely-used Ruby implementation of the query language GraphQL. It provides a simple, expressive and efficient way to build APIs. However, if you're using a vulnerable version of the library, an attacker can potentially execute arbitrary code on your system.

In this article, we'll explore the details of the vulnerability CVE-2025-27407, which affects GraphQL-Ruby versions 1.11.5 through to versions prior to 1.11.8, 1.12.25, 1.13.24, 2..32, 2.1.14, 2.2.17, and 2.3.21. We'll also provide code snippets and references to help you understand the issue and how to apply the appropriate patches.

Vulnerable Versions and Exploit Details

The vulnerability resides in the method GraphQL::Schema.from_introspection and GraphQL::Schema::Loader.load, which load schema data from JSON files. If an attacker can supply a malicious schema definition to your system - for example, through the use of GraphQL::Client, which loads external schemas via GraphQL introspection - they can potentially execute remote code on your system.

To give you a better idea of what this might look like, here's a code snippet demonstrating the issue:

# json_data would be the schema definition from introspection
json_data = {
  "data" => {
    "__schema" => {
      # ...
      "types" => [
        # ...
        {
          "fields" => nil,
          "some_key" => "Comment",
          "name" => "attacker_controlled_value",
          "provided_by" => "kernel_1",
          "kind" => "CUSTOM",
          # ...
        }
        # ...
      ]
    }
  }
}

# Load the schema from the json_data
# This would execute the attacker-controlled code
schema = GraphQL::Schema.from_introspection(json_data)

As you can see, an attacker-controlled value in the schema definition could lead to remote code execution.

Resolution

The maintainers of GraphQL-Ruby have released patches for the following versions: 1.11.8, 1.12.25, 1.13.24, 2..32, 2.1.14, 2.2.17, and 2.3.21.

If you're running one of the affected versions, you should update your graphql-ruby gem immediately to one of these versions or later:

gem 'graphql', '>= 1.11.8'
gem 'graphql', '>= 1.12.25'
gem 'graphql', '>= 1.13.24'
gem 'graphql', '>= 2..32'
gem 'graphql', '>= 2.1.14'
gem 'graphql', '>= 2.2.17'
gem 'graphql', '>= 2.3.21'

And then run

bundle update graphql

Check out these references for more information about the vulnerability and how to handle it

- Original GitHub Security Advisory
- CVE Details
- GitHub GraphQL-Ruby Repository

Conclusion

It is essential to maintain your applications up-to-date and keep track of security vulnerabilities in the libraries you use. While it was possible to have remote code execution in certain situations using vulnerable versions of GraphQL-Ruby, the issue has been resolved in the mentioned patch versions. Be sure to update your graphql-ruby gem to protect your systems against any malicious schema definition that could potentially harm your system.

Timeline

Published on: 03/12/2025 19:15:40 UTC
Last modified on: 03/12/2025 21:15:42 UTC