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.
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.014 (72.2th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 72nd percentile — 72.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.208 · newest: 0.014 · change: -0.194
Affected products
- Lfprojects Mlflow
- Mlflow Mlflow/mlflow — versions unspecified
Weakness classification (CWE)
References
- huntr.com/bounties/5aeff5f0-49c7-4180-b5cb-c9a046f16756 (Exploit, Third Party Advisory, Mitigation)
- github.com/mlflow/mlflow/commit/bb62e773263c14e9ba4d1a82fe72d0de2442c6aa (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.