# CVE-2023-6976: Unrestricted Upload of File with Dangerous Type

> Attackers can upload arbitrary files to any location on the server, potentially leading to remote code execution.

- **Severity:** High 8.8 (`CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 20 Dec 2023
- **Updated:** 2 Aug 2024
- **Also known as:** BIT-mlflow-2023-6976, GHSA-wv8q-4f85-2p8p, PYSEC-2026-1662

## What is CVE-2023-6976?

CVE-2023-6976 is a high-severity vulnerability in Lfprojects Mlflow, published on 20 Dec 2023. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

This vulnerability is capable of writing arbitrary files into arbitrary locations on the remote filesystem in the context of the server process.

Weakness: CWE-434 (Unrestricted Upload of File with Dangerous Type)

## Which versions are affected by CVE-2023-6976?

4 open source packages ship an affected version, including mlflow. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `mlflow` | Bitnami | All versions | 2.9.2 |
| `mlflow` | PyPI | All versions | 2.9.2 |
| `mlflow` | PyPI | All versions | 2.9.2 |
| `mlflow` | PyPI | All versions | 2.9.2 |

Products: Lfprojects Mlflow.

## How do I fix CVE-2023-6976?

Upgrade mlflow to 2.9.2 or later.

## Is CVE-2023-6976 being exploited?

There is no known exploitation of CVE-2023-6976 in the wild and no public exploit code.

## Other vulnerabilities in Lfprojects Mlflow

- [CVE-2026-64849](https://insights.sbomify.com/CVE-2026-64849/): MLflow Server-Side Request Forgery (critical 9.3, exploited in the wild)
- [CVE-2025-15379](https://insights.sbomify.com/CVE-2025-15379/): Command Injection in mlflow/mlflow (critical 10.0)
- [CVE-2024-0520](https://insights.sbomify.com/CVE-2024-0520/): Remote Code Execution due to Full Controlled File Write in mlflow/mlflow (critical 10.0)
- [CVE-2023-6977](https://insights.sbomify.com/CVE-2023-6977/): Path Traversal: '\..\filename' (critical 10.0)
- [CVE-2023-6709](https://insights.sbomify.com/CVE-2023-6709/): Improper Neutralization of Special Elements Used in a Template Engine in mlflow/mlflow (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-6976 and fix it if it is affected.

What it is: CVE-2023-6976 is a high-severity vulnerability in Lfprojects Mlflow, published on 20 Dec 2023. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-6976 in the wild and no public exploit code.

Affected packages and fixed versions:
- mlflow (Bitnami): affected all versions; fixed in 2.9.2
- mlflow (PyPI): affected all versions; fixed in 2.9.2
- mlflow (PyPI): affected all versions; fixed in 2.9.2
- mlflow (PyPI): affected all versions; fixed in 2.9.2

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-2023-6976/ (Markdown: https://insights.sbomify.com/CVE-2023-6976/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-6976
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-6976
- OSV: https://osv.dev/vulnerability/CVE-2023-6976

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-6976/
Summaries are generated and may contain mistakes; the official description above is the record.