CVE-2026-8355
Received Received - Intake

SSRF in IBM ContextForge MCP Gateway via OAuth Token URL

Publication date: 2026-10-20

Last updated on: 2026-10-20

Assigner: IBM Corporation

Description
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.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-10-20
Last Modified
2026-10-20
Generated
2026-10-20
AI Q&A
2026-10-20
EPSS Evaluated
N/A
NVD
CVE-2026-8355
EUVD
EUVD-2026-104673

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
IBM ContextForge MCP Gateway 0.1.0

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-918 The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

IBM ContextForge MCP Gateway versions 0.1.0 through 1.0.5 have a server-side request forgery (SSRF) vulnerability in the OAuth gateway registration feature. An authenticated user with gateway creation privileges can register a gateway with malicious OAuth configuration URLs. The system fails to validate these URLs, allowing the gateway to make arbitrary HTTP POST requests to internal network resources or cloud metadata endpoints. The vulnerability occurs due to improper validation of the oauth_config.token_url parameter during OAuth-enabled gateway registration.

Detection Guidance

Monitor outbound HTTP POST requests from the IBM ContextForge MCP Gateway service, particularly to internal network resources, cloud metadata endpoints (AWS IMDSv1, GCP, Azure), or localhost-bound services. Check for HTTP 502 errors with response bodies containing up to 256 characters of unexpected data, which may indicate exploitation.

Impact Analysis

This vulnerability allows an attacker to send HTTP POST requests to internal services, cloud metadata endpoints (AWS IMDSv1, GCP, Azure), or localhost-bound services. If the targeted service responds with invalid OAuth token data, up to 256 characters of the response may be exposed in an HTTP 502 error message. This could lead to information disclosure or unauthorized actions depending on the internal services accessed.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive internal systems or cloud metadata endpoints, potentially exposing confidential data. This may violate compliance requirements under GDPR (data protection) or HIPAA (health information privacy) if personal or health data is disclosed. Organizations should remediate this issue to maintain regulatory compliance.

Mitigation Strategies
  • Upgrade IBM ContextForge MCP Gateway to version 1.0.6 or later.
  • Remove the gateways.create permission from untrusted roles.
  • Implement network-level egress controls to block outbound requests to cloud metadata endpoints, RFC 1918 private IP ranges, and loopback addresses.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-8355. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart