CVE-2026-127202

Description

MLflow before 3.18.0 using the FileStore backend contains a path traversal vulnerability that allows unauthenticated remote attackers to write files outside the intended run directory by supplying a malicious model_id parameter to the log outputs API. Attackers can exploit the unvalidated model_id containing ../ sequences via the POST /api/3.0/mlflow/runs/outputs endpoint to create directories and write a meta.yaml file at arbitrary filesystem locations, limited only by the server account's permissions. FileStore was the default backend before 3.7.0 and is opt-in afterward through MLFLOW_ALLOW_FILE_STORE.

References

• https://github.com/mlflow/mlflow/commit/ab5fc795eedc22348253cf687818cf2a16c15282
• https://github.com/mlflow/mlflow/pull/27131
• https://github.com/mlflow/mlflow/releases/tag/v3.18.0
• https://www.vulncheck.com/advisories/mlflow-path-traversal-via-model-id-in-log-outputs-api