CVE-2026-40100 FastGPT has Unauthenticated SSRF in /api/core/app/mcpTools/runTool via missing CHECK_INTERNAL_IP default

What is CVE-2026-40100?

CVE-2026-40100 is a medium-severity server-side request forgery vulnerability in labring FastGPT, published on 10 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

FastGPT is an AI Agent building platform. Prior to 4.14.10.3, the /api/core/app/mcpTools/runTool endpoint accepts arbitrary URLs without authentication. The internal IP check in isInternalAddress() only blocks private IPs when CHECK_INTERNAL_IP=true, which is not the default. This allows unauthenticated attackers to perform SSRF against internal network resources. This vulnerability is fixed in 4.14.10.3.

Weakness: CWE-918

Which versions are affected by CVE-2026-40100?

It affects 1 product.

Products include Fastgpt Fastgpt.

How do I fix CVE-2026-40100?

No fix has been published for CVE-2026-40100 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-2026-40100 being exploited?

There is no known exploitation of CVE-2026-40100 in the wild and no public exploit code.

Other vulnerabilities in labring FastGPT

• CVE-2026-34162 FastGPT: Unauthenticated SSRF via httpTools Endpoint Leads to Internal API Key Theft Critical 10.0
• CVE-2026-40351 FastGPT: NoSQL Injection in loginByPassword leads to Authentication Bypass Critical 9.8
• CVE-2026-33075 FastGPT has Arbitrary Code Execution in GitHub Actions via pull_request_target in fastgpt-preview-image.yml Critical 9.4
• CVE-2026-40352 FastGPT: NoSQL Injection in updatePasswordByOld Leads to Account Takeover High 8.8
• CVE-2026-34163 Server-Side Request Forgery via MCP Tools Endpoint in FastGPT High 7.7

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-jrhc-f3j7-f8g4.