8.1

CVSS Score

3.0

-

CVSS Score

Basic Information

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CVE-2025-14279

CVE-2025-14279: MLFlow is vulnerable to DNS rebinding attacks due to a lack of Origin header validation

MLFlow versions up to and including 3.4.0 are vulnerable to DNS rebinding attacks due to a lack of Origin header validation in the MLFlow REST server. This vulnerability allows malicious websites to bypass Same-Origin Policy protections and execute unauthorized calls against REST endpoints. An attacker can query, update, and delete experiments via the affected endpoints, leading to potential data exfiltration, destruction, or manipulation. The issue is resolved in version 3.5.0.

(GitHub Advisory)

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CVE-2025-14279

CVE-2025-14279:

8.1

CVSS Score

3.0

-

CVSS Score

Basic Information

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Technical Details

Package Name	Ecosystem	Vulnerable Versions	First Patched Version
mlflow	pip	< 3.5.0	3.5.0

Technical Details

Vulnerability Intelligence
Miggo AI

Root Cause Analysis

The vulnerability, CVE-2025-14279, is a DNS rebinding attack in the MLflow tracking server, caused by a lack of 'Host' header validation. This allowed malicious websites to make unauthorized API calls to the server, bypassing same-origin policy.

The patch addresses this by introducing a security middleware layer for both the Flask and FastAPI server implementations. This middleware intercepts all incoming requests and validates the Host header against a configurable allowlist.

The analysis identified the key functions and methods that were added to implement this security control. The vulnerability lies in the absence of these functions in versions prior to the patch. The identified functions are:

mlflow.server.fastapi_app.create_fastapi_app: In vulnerable versions, this function was responsible for creating the FastAPI server without the necessary security middleware. The patch modifies it to include the middleware initialization.
mlflow.server.security.validate_host: This function, added for the Flask server, contains the logic to validate the Host header. It is registered to run before each request. Its absence in vulnerable versions is a direct cause of the vulnerability.
mlflow.server.fastapi_security.HostValidationMiddleware.__call__: This is the equivalent of validate_host for the FastAPI server. Its absence meant no Host header validation was performed.

By identifying these functions, we can understand that the vulnerability was not a flaw in a specific existing function, but a missing security control at the application level. Any REST API endpoint that modifies state (e.g., creating, updating, or deleting experiments) was effectively vulnerable because the server framework did not reject requests from unauthorized hosts.

Vulnerable functions

mlflow.server.fastapi_app.create_fastapi_app

mlflow/server/fastapi_app.py

This function creates the FastAPI application that runs the MLflow server. Prior to the patch, it did not initialize any security middleware to validate the 'Host' header of incoming requests. This absence of validation is what allowed DNS rebinding attacks, as any request would be processed by the API endpoints regardless of the 'Host' header. The patch adds the `init_fastapi_security(fastapi_app)` call to install the necessary security middleware.

mlflow.server.security.validate_host

mlflow/server/security.py

This function is part of the security middleware added for the Flask-based server. It is registered as a `before_request` hook to validate the `Host` header of every incoming request. The vulnerability existed because this function and its validation logic were completely absent, meaning the server did not perform any `Host` header validation, leaving it vulnerable to DNS rebinding attacks. Any REST API endpoint could be targeted as a result.

mlflow.server.fastapi_security.HostValidationMiddleware.__call__

mlflow/server/fastapi_security.py

This middleware function is the equivalent of `validate_host` for the FastAPI-based server. It intercepts incoming HTTP requests to validate the `Host` header against an allowed list. The vulnerability existed due to the absence of this middleware. Without it, requests with malicious `Host` headers were passed on to the application's endpoints, enabling DNS rebinding attacks.

Vulnerability Intelligence
Miggo AI

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WAF Rule

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Reasoning

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