CVE-2025-27098: Missing Check Vulnerability in GraphQL Mesh's Static File Handler

GraphQL Mesh is a popular and flexible gateway that allows developers to integrate multiple APIs and services seamlessly. However, a missing check vulnerability in its static file handler leaves GraphQL Mesh susceptible to potential attacks, and even exposes the server's file system to unauthorized access.

This article discusses the details of the vulnerability (CVE-2025-27098), its potential impact, and the recommended solutions to fix it.

Vulnerability Description

The vulnerability originates from the static-file-handler.ts file of the graphql-mesh package, used for handling static files in the server's file system. When the staticFiles setting is enabled in the serve section of the configuration file, the handler fails to check if the absolutePath is under the provided directory. Consequently, unauthorized clients can access or exploit files outside the specific directory, leading to potential data leaks or system compromises.

Here's how the vulnerability manifests in the code

const absolutePath = path.join(staticFiles, reqUrl.pathname);
const fileExists = await fs.pathExists(absolutePath);

if (fileExists) {
  const fileStream = fs.createReadStream(absolutePath);
  fileStream.pipe(res);
}

Exploitation of the Vulnerability

Attackers could exploit this vulnerability by manipulating the reqUrl.pathname to gain unauthorized access to files or sub-directories on the server. Further, they can execute arbitrary code, cause denial of service, or even exfiltrate sensitive information—depending on the files exposed.

References

Find more details about GraphQL Mesh in its official documentation here and the original issue report on its GitHub repository here.

Users have two options to fix the vulnerability

1. Update the appropriate packages: If you are using @graphql-mesh/cli, update it to a version higher than .82.21. If you are using @graphql-mesh/http, update it to a version higher than .3.18. Here's how to update these packages:

$ npm install @graphql-mesh/cli@latest
$ npm install @graphql-mesh/http@latest

2. Remove the staticFiles option from the configuration file and use alternative solutions to serve static files. For instance, you could use the popular Express or Fastify web servers to serve static files, ensuring an additional layer of security.

// With Express
const express = require('express');
const app = express();
app.use(express.static('public'));
app.listen(300, () => console.log('Server started on port 300'));

// With Fastify
const fastify = require('fastify')();
fastify.register(require('fastify-static'), { root: path.join(__dirname, 'public') });
fastify.listen(300, () => console.log('Server started on port 300'));

Conclusion

This article highlights the importance of regularly auditing software components to identify and fix security vulnerabilities. GraphQL Mesh users should promptly apply the recommended updates or remove the staticFiles option to safeguard their servers against potential attacks and unauthorized access.

Timeline

Published on: 02/20/2025 21:15:26 UTC
Last modified on: 02/27/2025 20:27:05 UTC