MEDIUM 6.6 GitHub
CVE-2026-53708
ContextForge: DNS TOCTOU race condition causes SSRF protection bypass (`/admin/gateways/test`)
## Summary
The `/admin/gateways/test` endpoint validates submitted URLs by resolving the hostname at validation time and blocking private address ranges. The HTTP client independently re-resolves DNS at connection time with no IP binding between the two operations, creating a TOCTOU window exploitable via DNS rebinding. The source code explicitly acknowledges this limitation in two separate locations.
## Details
`validate_gateway_test_url()` in `mcpgateway/common/validators.py` (lines 1527–17
Affected Products
- pip/mcp-contextforge-gateway < 1.0.3
References
- https://github.com/advisories/GHSA-9hgc-g3w5-67cm
- https://github.com/IBM/mcp-context-forge/security/advisories/GHSA-9hgc-g3w5-67cm
- https://github.com/IBM/mcp-context-forge/releases/tag/v1.0.3
- https://github.com/advisories/GHSA-9hgc-g3w5-67cm
This medium severity vulnerability with a CVSS score of 6.6 was published on 2026-08-14 via GitHub. Affected: pip/mcp-contextforge-gateway < 1.0.3.
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