MLflow Use of Default Password Authentication Bypass Vulnerability

February 19th, 2026
ZDI-26-111 ZDI-CAN-28256

CVE ID

CVE-2026-2635

CVSS Score

9.8 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors

MLflow

Affected Products

MLflow

Vulnerability Details

This vulnerability allows remote attackers to bypass authentication on affected installations of MLflow. Authentication is not required to exploit this vulnerability.

The specific flaw exists within the basic_auth.ini file. The file contains hard-coded default credentials. An attacker can leverage this vulnerability to bypass authentication and execute arbitrary code in the context of the administrator.

Additional Details

Fixed in version 3.16.1
https://github.com/mlflow/mlflow/pull/25751


Disclosure Timeline

  • 2025-10-14 - Vulnerability reported to vendor
  • 2026-02-19 - Coordinated public release of advisory
  • 2026-10-20 - Advisory Updated

Credit

Peter Girnus (@gothburz) of Trend Zero Day Initiative

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