CVE-2026-2652CWE-305

Authentication Bypass in mlflow/mlflow

High · published May 15, 2026

CVSS v3.0
8.6
EPSS
1%
Percentile
72.4
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.0
8.6 · HIGH
Vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L
CVSS v4.0
Not supplied
EPSS
0.01409 · 72.4th percentile
Weakness
CWE-305 · Authentication Bypass by Primary Weakness
Published
2026-05-15T02:13Z
EPSS history
Timeline
  • 25 SEP 03:25Z
    EPSS moved 21% → 1%
    epss
  • 15 MAY 02:13Z
    Authentication Bypass in mlflow/mlflow
    cvelistv5