# CVE-2026-32128: FastGPT Python Sandbox Bypass of File-Write Restriction

> Attackers can bypass file-write restrictions in FastGPT's Python Sandbox by remapping stdout, enabling arbitrary file creation or overwrites within the container.

- **Severity:** Medium 6.3 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 11 Mar 2026
- **Updated:** 12 Mar 2026
- **Also known as:** GHSA-6hw6-mxrm-v6wj

## What is CVE-2026-32128?

CVE-2026-32128 is a medium-severity vulnerability in labring FastGPT, published on 11 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. In 4.14.7 and earlier, FastGPT's Python Sandbox (fastgpt-sandbox) includes guardrails intended to prevent file writes (static detection + seccomp). These guardrails are bypassable by remapping stdout (fd 1) to an arbitrary writable file descriptor using fcntl. After remapping, writing via sys.stdout.write() still satisfies the seccomp rule write(fd==1), enabling arbitrary file creation/overwrite inside the sandbox container despite the intended no file writes restriction.

Weakness: CWE-184 (Incomplete List of Disallowed Inputs)

## Which versions are affected by CVE-2026-32128?

It affects 1 product.


Products: Fastgpt Fastgpt.

## How do I fix CVE-2026-32128?

No fix has been published for CVE-2026-32128 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-32128 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-32128 exists.

Public exploit code:

- FastGPT Python sandbox escape chain audit tool (CVE-2026-32128 related, v4.14.8 inspect chain) (github_poc): https://github.com/qianlijaingshan/fastgpt-sandbox-audit

## 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-2026-32128 and fix it if it is affected.

What it is: CVE-2026-32128 is a medium-severity vulnerability in labring FastGPT, published on 11 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-32128 exists.

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-2026-32128/ (Markdown: https://insights.sbomify.com/CVE-2026-32128/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-32128
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-32128
- OSV: https://osv.dev/vulnerability/CVE-2026-32128

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-32128/
Summaries are generated and may contain mistakes; the official description above is the record.