How to Fix CVE-2025-27407: A Critical Remote Code Execution Vulnerability in graphql-ruby?

graphql-ruby, a popular Ruby implementation of GraphQL, has recently been found vulnerable to a critical remote code execution (RCE) flaw. Tracked as CVE-2025-27407, this vulnerability allows attackers to potentially execute arbitrary code remotely, posing a significant threat to systems using the library. This article aims to provide security professionals with a comprehensive understanding of the vulnerability, its potential impact, and most importantly, how to effectively mitigate it.

This article provides a deep dive into the vulnerability, covering technical details, affected versions, and practical steps to protect your systems. It aims to equip security professionals with the knowledge and guidance necessary to promptly address this critical issue, ensuring the security and integrity of their applications.

A Short Introduction to graphql-ruby

graphql-ruby is a widely-used Ruby library that implements the GraphQL specification. It enables developers to build GraphQL APIs and integrate them into Ruby applications. GraphQL is a query language for APIs and a runtime for fulfilling those queries with your existing data. It provides a more efficient, powerful, and flexible alternative to RESTful APIs. Because of its popularity, any vulnerability can have widespread implications.

Summary of CVE-2025-27407

CVE-2025-27407 is a critical remote code execution vulnerability in graphql-ruby that affects versions prior to 1.11.8, 1.12.25, 1.13.24, 2.0.32, 2.1.14, 2.2.17, and 2.3.21. The vulnerability arises when loading a malicious schema definition using GraphQL::Schema.from_introspection or GraphQL::Schema::Loader.load methods. An attacker can exploit this by crafting a malicious JSON schema and tricking the application into loading it from an untrusted source. Due to the ability to execute arbitrary code, the severity is marked as critical.

Impact of CVE-2025-27407

The impact of CVE-2025-27407 is severe. A successful exploit could allow attackers to execute arbitrary code execution remotely, potentially leading to a complete compromise of the affected system. This can result in unauthorized access to sensitive data, data theft, system manipulation, or even a complete system takeover. Systems that use GraphQL::Client to load external schemas via GraphQL introspection are particularly vulnerable.

The vulnerability poses a critical risk to organizations relying on graphql-ruby for their APIs, making prompt mitigation essential. Organizations should assess the exposure of their systems and prioritize patching or implementing mitigations to minimize the potential for exploitation and data loss. The ability to execute arbitrary code remotely makes this a high-priority vulnerability to address.

Products Affected by CVE-2025-27407

The following versions of graphql-ruby are affected by this vulnerability:

Any application using these versions and loading schemas from untrusted sources is potentially vulnerable.

How to Check Your Product is Vulnerable?

To determine if your application is vulnerable, verify the version of the graphql-ruby gem you are using. You can do this by checking your Gemfile.lock or by running bundle show graphql in your project directory. If you have splunk instances it will be easy to identify.

Next, examine your code for instances where you use GraphQL::Schema.from_introspection or GraphQL::Schema::Loader.load. Pay close attention to where the schema definition originates. If the schema is loaded from an external, untrusted source, your application is at risk. Specifically, check for instances where you use GraphQL::Client to load external schemas via GraphQL introspection because those cases are especially vulnerable.

How to Fix CVE-2025-27407?

The primary remediation strategy is to upgrade your graphql-ruby gem to one of the patched versions: 1.11.8, 1.12.25, 1.13.24, 2.0.32, 2.1.14, 2.2.17, or 2.3.21. Mitigating remote code execution vulnerabilities is an imporatant part of cybersecurity.

By following these steps, you can effectively mitigate the risk posed by CVE-2025-27407 and protect your applications from potential remote code execution attacks.

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