IBM ContextForge MCP Gateway is affected by server-side request forgery

Overview

IBM ContextForge MCP Gateway 0.1.0 through 1.0.5 is vulnerable to a server-side request Forgery (SSRF) that allows authenticated users with gateway creation privileges to perform arbitrary HTTP POST requests to internal network resources and cloud metadata endpoints. The vulnerability occurs during OAuth-enabled gateway registration when the system fails to validate the oauth_config.token_url parameter. When registering a gateway with OAuth client credentials authentication, an attacker can supply a malicious token_url pointing to internal services, cloud metadata endpoints (AWS IMDSv1, GCP, Azure), or localhost-bound services. The application immediately performs an HTTP POST request to the attacker-controlled URL with form-encoded credentials in the body. If the response cannot be parsed as a valid OAuth token response, up to 256 characters of the response body are reflected back to the attacker in the HTTP 502 error message. This vulnerability bypasses existing SSRF protections that are applied to the gateway.url field but not to OAuth configuration parameters.

Affected

• contextforge_mcp_gateway >= 0.1.0 <= 1.0.5

Remediation

IBM strongly recommends addressing the vulnerability now.

Product(s)Version(s) number and/or range Remediation/Fix/InstructionsIBM ContextForge MCP Gateway

2.0>=v1.0.6Upgrade to v1.0.6 or later. See release notes:  https://github.com/IBM/mcp-context-forge/releases/tag/v1.0.6 https://github.com/IBM/mcp-context-forge/releases/tag/v1.0.6%29

Workarounds

If an immediate upgrade to v1.0.6 is not possible, restrict access to the gateway registration API:

• Remove the gateways.create permission from the developer role or any role assigned to untrusted users.

• Enforce network-level egress controls (firewall / security group rules) to block outbound HTTP/HTTPS from the gateway host to cloud metadata addresses (169.254.254.169/32, fd00:ec2::254/128), RFC 1918 ranges, and loopback (127.0.0.0/8).

IBM strongly recommends upgrading to the fixed version as soon as possible.