Vulnerability in Lfprojects Mlflow
CVE-2026-2652
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.
EPSS: 0.208 (97.4th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.6 (High). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L.
Affected products
- Lfprojects Mlflow
- Mlflow Mlflow/mlflow — versions unspecified
Weakness classification (CWE)
References
- security@huntr.dev (Exploit, Third Party Advisory, Mitigation)
- security@huntr.dev (Patch)
Frequently asked questions
- What is CVE-2026-2652?
- CVE-2026-2652 is a high-severity vulnerability in Lfprojects Mlflow, classified under Authentication Bypass by Primary Weakness. CVSS score: 8.6/10. Published 2026-05-15.
- How severe is CVE-2026-2652?
- High severity. CVSS v3 base score is 8.6 out of 10.