# CVE-2026-18905: IBM ContextForge MCP Gateway DNS rebinding SSRF

Source: https://junglewise.ai/threats/cve-2026-18905-ibm-contextforge-mcp-gateway-dns-rebinding-ssrf  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-04. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-18905 · Severity: high · CVSS 7.7 · Published 2026-09-04

IBM ContextForge MCP Gateway is a tool that manages REST-based integrations for AI workflows. An authenticated user can exploit a DNS rebinding vulnerability to redirect the gateway's outbound requests to internal network systems, potentially exposing sensitive data or accessing restricted resources that should not be accessible from the internet.

Technologies: [IBM Contextforge](https://junglewise.ai/threats/technologies/contextforge), [IBM ContextForge MCP Gateway](https://junglewise.ai/threats/technologies/contextforge-mcp-gateway). Vendors: [IBM](https://junglewise.ai/threats/vendors/ibm).

## Quick answers

**Is CVE-2026-18905 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-18905 being exploited in the wild.

**How severe is CVE-2026-18905?** High severity, with a CVSS score of 7.7, published 4 September 2026.

**Which products and versions are affected?** IBM ContextForge MCP Gateway ≤ v1.0.6.

**Is there a fix for CVE-2026-18905?** A patch was published on 2026-07-29: Fix merged in PR #5925; v1.0.7 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-18905 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-18905?** Check whether you run IBM Contextforge or IBM ContextForge MCP Gateway at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a server-side request forgery (SSRF) via DNS time-of-check-time-of-use (TOCTOU) weakness. The MCP Gateway validates REST tool target URLs for SSRF only during tool registration, but reuses the stored URL without re-validation or DNS pinning during subsequent tool invocation. An authenticated attacker registers a tool with a controlled hostname, then changes the DNS record after registration to point to an internal target. When the tool is invoked, the gateway resolves the hostname again, fetching the attacker's updated DNS record and sending requests to the internal address. No user interaction is required. The fix is available in v1.0.7 and higher.

## Affected products

- IBM ContextForge MCP Gateway ≤ v1.0.6

## Timeline

- 2026-09-02: disclosed
- 2026-07-29: patched: Fix merged in PR #5925; v1.0.7 released

## References

- [https://www.ibm.com/support/pages/node/7286053](https://www.ibm.com/support/pages/node/7286053)

## Related threats

- [IBM ContextForge MCP Gateway denial of service in tool slug normalization](https://junglewise.ai/threats/cve-2026-18484-ibm-contextforge-mcp-gateway-1-0-0-through-1-0-11-could-allow-a)
- [IBM ContextForge MCP Gateway server-side request forgery in OAuth registration](https://junglewise.ai/threats/cve-2026-8355-ibm-contextforge-mcp-gateway-0-1-0-through-1-0-5-is-vulnerable-to)
- [IBM ContextForge MCP Gateway path traversal in Admin API](https://junglewise.ai/threats/cve-2026-77825-ibm-contextforge-mcp-gateway-1-0-0-through-1-0-8-was-vulnerable)
- [IBM ContextForge MCP Gateway protection bypass in nested payload inspection](https://junglewise.ai/threats/cve-2026-11918-ibm-contextforge-mcp-gateway-protection-bypass-in-nested-payload)
- [IBM ContextForge MCP Gateway default credentials auth bypass](https://junglewise.ai/threats/cve-2026-78573-ibm-contextforge-mcp-gateway-default-credentials-auth-bypass)