ZDI-26-111: MLflow Use of Default Password Authentication Bypass Vulnerability
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 basicauth.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.
Other sources
This vulnerability allows remote attackers to bypass authentication on affected installations of MLflow. Authentication is not required to exploit this vulnerability. The ZDI has assigned a CVSS rating of 9.8. The following CVEs are assigned: CVE-2026-2635.
— ZDI
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
mlflowto a version that resolves this vulnerability.Patch ZDI-26-111 - Configuration
Edit the MLflow basic_auth.ini file to eliminate the hard-coded default credentials and replace them with unique credentials.
MLflow (basic_auth.ini) default credentials (hard-coded in basic_auth.ini) = Remove/update hard-coded default credentials to unique, strong credentials
Event History
Frequently Asked Questions
What is the severity of ZDI-26-111?
ZDI-26-111 is classified as a critical vulnerability due to its ability to allow unauthenticated access to MLflow installations.
How do I fix ZDI-26-111?
To fix ZDI-26-111, users should disable default passwords and properly configure authentication in the basic_auth.ini file.
Which versions of MLflow are affected by ZDI-26-111?
ZDI-26-111 affects all impacted installations of MLflow that utilize default password settings.
What is the impact of ZDI-26-111 on data security?
The impact of ZDI-26-111 includes potential unauthorized access to sensitive data and control over MLflow resources.
Are there any workaround measures for ZDI-26-111 until a fix is applied?
As a workaround for ZDI-26-111, users can temporarily restrict network access to MLflow instances to trusted sources only.