Vulnerability · Published Oct 27, 2026 · Assigned by GitHub_M
CVE-2026-116692MLflow: Remote code execution on unauthenticated MLflow servers via third-party scorer deserialization importing caller-placed artifact modules
Critical 9.8
In plain English
A critical-severity code injection in mlflow from mlflow. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 53% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.
Official description
MLflow is an open source AI engineering platform for agents, large language models, and machine learning models. From 3.12.0rc0 until 3.17.0, third-party scorer deserialization in mlflow/genai/scorers/base.py accepts request-selected descendants of THIRD_PARTY_SCORER_ALLOWED_MODULES rather than requiring an exact allowed module. A caller can use MLflow artifact endpoints to place a Python module beneath a writable allowed package and submit its module and class through /ajax-api/3.0/mlflow/scorer/invoke. Scorer.model_validate_json() imports the module and constructs the class before trace processing. Authentication-disabled deployments permit this code execution without credentials, while basic-auth deployments require a principal capable of creating an experiment and run and uploading artifacts. In either configuration, the allowed scorer package must be writable by the server process. This issue is fixed in version 3.17.0.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | mlflow | 3.17.0 | GHSA-26p8-2jq9-3vq9 |
Affected products (as reported)
Weakness: CWE-94, CWE-470 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- https://github.com/mlflow/mlflow/security/advisories/GHSA-26p8-2jq9-3vq9 x_refsource_CONFIRM
- https://github.com/mlflow/mlflow/pull/25906 x_refsource_MISC
- https://github.com/mlflow/mlflow/commit/a732443e695c3c677680c54320efc394c81654ab x_refsource_MISC
- https://github.com/mlflow/mlflow/releases/tag/v3.17.0 x_refsource_MISC