CVE-2026-34163 Server-Side Request Forgery via MCP Tools Endpoint in FastGPT
An authenticated attacker can exploit missing SSRF protection in FastGPT MCP endpoints to scan internal networks and access sensitive internal services.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-34163?
CVE-2026-34163 is a high-severity server-side request forgery vulnerability in labring FastGPT, published on 31 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
FastGPT is an AI Agent building platform. Prior to version 4.14.9.5, FastGPT's MCP (Model Context Protocol) tools endpoints (/api/core/app/mcpTools/getTools and /api/core/app/mcpTools/runTool) accept a user-supplied URL parameter and make server-side HTTP requests to it without validating whether the URL points to an internal/private network address. Although the application has a dedicated isInternalAddress() function for SSRF protection (used in other endpoints like the HTTP workflow node), the MCP tools endpoints do not call this function. An authenticated attacker can use these endpoints to scan internal networks, access cloud metadata services, and interact with internal services such as MongoDB and Redis. This issue has been patched in version 4.14.9.5.
Weakness: CWE-918
Which versions are affected by CVE-2026-34163?
It affects 1 product.
Products include Fastgpt Fastgpt.
How do I fix CVE-2026-34163?
No fix has been published for CVE-2026-34163 yet. Limit exposure of the affected software until one is available.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-34163 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34163 exists.
Other vulnerabilities in labring FastGPT
- CVE-2026-34162 FastGPT: Unauthenticated SSRF via httpTools Endpoint Leads to Internal API Key Theft
- CVE-2026-40351 FastGPT: NoSQL Injection in loginByPassword leads to Authentication Bypass
- CVE-2026-33075 FastGPT has Arbitrary Code Execution in GitHub Actions via pull_request_target in fastgpt-preview-image.yml
- CVE-2026-40352 FastGPT: NoSQL Injection in updatePasswordByOld Leads to Account Takeover
- CVE-2026-26075 Cross-Site Request Forgery (CSRF) in FastGPT
Sources
Also known as GHSA-x9vj-5m4j-9mfv.