CVE-2025-27098: GraphQL Mesh CLI Path Traversal Flaw

CVE-2025-27098 Overview

CVE-2025-27098 is a path traversal vulnerability in GraphQL Mesh, a popular GraphQL Federation framework and gateway that supports both GraphQL Federation and non-GraphQL Federation subgraphs, as well as non-GraphQL services such as REST, gRPC, and databases including MongoDB, MySQL, and PostgreSQL. The vulnerability exists in the static file handler component and allows unauthenticated remote attackers to access arbitrary files on the server's file system.

Critical Impact

Remote attackers can exploit this vulnerability to read sensitive files from the server, potentially exposing configuration files, credentials, environment variables, source code, and other confidential data without authentication.

Affected Products

• the-guild graphql_mesh_cli (versions prior to 0.82.22)
• the-guild graphql_mesh_http (versions prior to 0.3.19)

Discovery Timeline

• 2025-02-20 - CVE CVE-2025-27098 published to NVD
• 2025-02-27 - Last updated in NVD database

Technical Details for CVE-2025-27098

Vulnerability Analysis

This path traversal vulnerability (CWE-22) exists within the static file handler of GraphQL Mesh. When the staticFiles option is configured in the serve settings of the configuration file, the handler fails to properly validate that the requested file path remains within the designated static files directory. This missing security check enables attackers to traverse outside the intended directory using path traversal sequences, gaining unauthorized access to arbitrary files on the server's file system.

The vulnerability is particularly dangerous because it can be exploited remotely over the network without any authentication or user interaction. An attacker who successfully exploits this vulnerability can read sensitive files that should not be accessible, including configuration files, application secrets, database credentials, and potentially source code.

Root Cause

The root cause is a missing validation check in the static file handler. When processing requests for static files, the handler constructs an absolutePath based on user input but does not verify whether this path remains within the bounds of the directory specified in the staticFiles configuration option. This allows attackers to use directory traversal sequences (such as ../) to escape the intended directory and access files elsewhere on the file system.

Attack Vector

The attack vector is network-based and requires no authentication or privileges. An attacker can craft malicious HTTP requests containing path traversal sequences targeting the static file endpoint. By manipulating the requested file path with sequences like ../, the attacker can navigate the directory structure and request files outside the designated static files directory.

For example, if the staticFiles directory is set to /app/public, an attacker could potentially request paths that resolve to sensitive locations like /etc/passwd, application configuration files, or environment files containing secrets. The vulnerability affects any GraphQL Mesh deployment that has the staticFiles option enabled in its configuration.

Detection Methods for CVE-2025-27098

Indicators of Compromise

• HTTP request logs containing path traversal sequences such as ../, ..%2f, or ..%5c targeting GraphQL Mesh endpoints
• Unusual access patterns to the static file handler with encoded or double-encoded traversal characters
• Access attempts to sensitive system files like /etc/passwd, .env, or configuration files through the GraphQL Mesh service
• Error logs indicating file access attempts outside the configured static files directory

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block path traversal patterns in HTTP requests
• Monitor application logs for requests containing directory traversal sequences targeting the static file handler
• Deploy intrusion detection systems (IDS) with signatures for common path traversal attack patterns
• Review access logs for unusual file access patterns or requests for system files

Monitoring Recommendations

• Enable detailed logging for the GraphQL Mesh service to capture all static file requests
• Set up alerts for any requests containing ../ or URL-encoded variants to static file endpoints
• Monitor for anomalous file read operations from the GraphQL Mesh process
• Implement file integrity monitoring for sensitive configuration files and directories

How to Mitigate CVE-2025-27098

Immediate Actions Required

• Update @graphql-mesh/cli to version 0.82.22 or higher immediately
• Update @graphql-mesh/http to version 0.3.19 or higher if used in your deployment
• If immediate patching is not possible, remove the staticFiles option from the configuration file as a temporary workaround
• Review server logs for any evidence of exploitation attempts

Patch Information

The Guild has released patched versions that address this vulnerability. Users should update to @graphql-mesh/cli version higher than 0.82.21 and @graphql-mesh/http version higher than 0.3.18. The fix implements proper path validation to ensure requested files remain within the configured static files directory. For more details, refer to the GitHub Security Advisory.

Workarounds

• Remove the staticFiles option from your GraphQL Mesh configuration file entirely
• Use alternative solutions to serve static files, such as a dedicated web server (nginx, Apache) or a CDN
• Implement a reverse proxy in front of GraphQL Mesh that validates and sanitizes file path requests
• Restrict network access to the GraphQL Mesh service using firewall rules while awaiting patch deployment

# Configuration example - Remove staticFiles from mesh configuration
# In your .meshrc.yaml or mesh.config.js, remove or comment out:
# serve:
#   staticFiles: ./public  # Remove this line

# Alternative: Use nginx to serve static files securely
# nginx configuration example:
# location /static/ {
#     alias /app/public/;
#     internal;
# }