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

> Unauthenticated attackers can perform Server-Side Request Forgery against internal resources due to a disabled default IP check.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 10 Apr 2026
- **Updated:** 15 Apr 2026
- **Also known as:** GHSA-jrhc-f3j7-f8g4

## 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 (Server-Side Request Forgery)

## Which versions are affected by CVE-2026-40100?

It affects 1 product.


Products: 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.

## 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](https://insights.sbomify.com/CVE-2026-34162/): FastGPT: Unauthenticated SSRF via httpTools Endpoint Leads to Internal API Key Theft (critical 10.0)
- [CVE-2026-40351](https://insights.sbomify.com/CVE-2026-40351/): FastGPT: NoSQL Injection in loginByPassword leads to Authentication Bypass (critical 9.8)
- [CVE-2026-33075](https://insights.sbomify.com/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](https://insights.sbomify.com/CVE-2026-40352/): FastGPT: NoSQL Injection in updatePasswordByOld Leads to Account Takeover (high 8.8)
- [CVE-2026-34163](https://insights.sbomify.com/CVE-2026-34163/): Server-Side Request Forgery via MCP Tools Endpoint in FastGPT (high 7.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-40100 and fix it if it is affected.

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

Affected product: labring FastGPT. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-40100/ (Markdown: https://insights.sbomify.com/CVE-2026-40100/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-40100
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40100
- OSV: https://osv.dev/vulnerability/CVE-2026-40100

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-40100/
Summaries are generated and may contain mistakes; the official description above is the record.