Description
FastGPT is an AI Agent building platform. Prior to version 4.14.17, FastGPT had an inconsistent SSRF protection gap in MCP tool URL handling. The direct MCP preview/run endpoints already rejected internal/private network URLs, but the MCP tool create/update endpoints could still save an internal MCP server URL. That stored URL could later be used by workflow execution without revalidating the destination. An authenticated user with permission to create or manage MCP toolsets could store an internal endpoint such as http://localhost:3000/mcp and later cause the FastGPT backend workflow runner to connect to that internal destination. This issue has been patched in version 4.14.17.
References6
- github.com/labring/FastGPT/commit/c1c6b9520d976d25ed945b5bc4e07…
- github.com/labring/FastGPT/pull/6826
- github.com/labring/FastGPT/releases/tag/v4.14.17
- github.com/labring/FastGPT/security/advisories/GHSA-cxxj-99f7-f…
- github.com/labring/FastGPT/pull/6826
- github.com/labring/FastGPT/security/advisories/GHSA-cxxj-99f7-f…
Metrics
- CVSS 3.1
-
6.3
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L - EPSS — exploit probability
- 0% percentile: 15 · as of 13 November 2026
- CWE
- CWE-918
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.