Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Lfprojects | Mlflow | < 3.10.0 |
Related Weaknesses (CWE)
References
- https://github.com/mlflow/mlflow/commit/bb62e773263c14e9ba4d1a82fe72d0de2442c6aaPatch
- https://huntr.com/bounties/5aeff5f0-49c7-4180-b5cb-c9a046f16756ExploitMitigationThird Party Advisory
- https://huntr.com/bounties/5aeff5f0-49c7-4180-b5cb-c9a046f16756ExploitMitigationThird Party Advisory
FAQ
What is CVE-2026-2652?
CVE-2026-2652 is a vulnerability with a CVSS score of 8.6 (HIGH). 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...
How severe is CVE-2026-2652?
CVE-2026-2652 has been rated HIGH with a CVSS base score of 8.6/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-2652?
Check the references section above for vendor advisories and patch information. Affected products include: Lfprojects Mlflow.