MLflow up to 3.17.1 FileStore trace_info.yaml FileStore.start_trace trace_id path traversal

Summaryinfo

A vulnerability classified as critical was found in MLflow up to 3.17.1. Affected by this vulnerability is the function FileStore.start_trace of the file trace_info.yaml of the component FileStore. Such manipulation of the argument trace_id leads to path traversal. This vulnerability is documented as CVE-2026-53995. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in MLflow up to 3.17.1. It has been rated as critical. Affected by this issue is the function FileStore.start_trace of the file trace_info.yaml of the component FileStore. The manipulation of the argument trace_id with an unknown input leads to a path traversal vulnerability. Using CWE to declare the problem leads to CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. Impacted is integrity, and availability. CVE summarizes:

MLflow 3.17.1 and earlier contains a path traversal vulnerability in the FileStore tracking backend that allows unauthenticated attackers to control filesystem paths by submitting a crafted trace ID containing traversal sequences to the POST /api/3.0/mlflow/traces endpoint. Attackers can exploit FileStore.start_trace() to write trace_info.yaml, request_metadata, and tag files with attacker-controlled metadata outside the intended experiment trace directory, subject to the server process's filesystem permissions. FileStore is the default tracking backend before MLflow 3.7.0 and opt-in thereafter (the default changed to a SQLite database), so deployments in the earlier part of the affected range are vulnerable without special configuration while later ones are affected only when FileStore is explicitly selected.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-53995 since 06/11/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 10/20/2026). The MITRE ATT&CK project declares the attack technique as T1006.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Name

• MLflow

Version

• 3.17.0
• 3.17.1

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CPE 2.2info

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