# CVE-2026-53995: MLflow < 3.18.0 Path Traversal via Trace ID API

Status: published. Published: 2026-10-19. Updated: 2026-11-13.

MLflow before 3.18.0 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.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/mlflow/mlflow/pull/26842
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/mlflow/mlflow/commit/d64cc8b673f71d29d93a7845fc179946ad56a881

## Affected products and versions

- mlflow / mlflow (mlflow/mlflow): ≥ 0; < 3.18.0 (affected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 8.8 (high); 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; source: CNA: VulnCheck

- CVSS 3.1: 8.2 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L; source: CNA: VulnCheck

- CVSS 4.0: 8.8 (high); 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 8.2 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: 0.63% as of 2026-11-13; percentile 50.52%

- SSVC: exploitation poc; automatable yes; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-22

## Exploit evidence

- exploit: https://github.com/SaiTeja-Erukude/CVE-2026-53995-mlflow-path-traversal (CNA: VulnCheck)

## References

- https://github.com/SaiTeja-Erukude/CVE-2026-53995-mlflow-path-traversal (CNA: VulnCheck; technical-description, exploit)

- https://github.com/mlflow/mlflow/releases/tag/v3.18.0 (CNA: VulnCheck; release-notes)

- https://github.com/mlflow/mlflow/pull/26842 (CNA: VulnCheck; issue-tracking, patch)

- https://github.com/mlflow/mlflow/commit/d64cc8b673f71d29d93a7845fc179946ad56a881 (CNA: VulnCheck; issue-tracking, patch)

- https://www.vulncheck.com/advisories/mlflow-path-traversal-via-trace-id-api (CNA: VulnCheck; third-party-advisory)

- https://github.com/SaiTeja-Erukude/CVE-2026-53995-mlflow-path-traversal (disclosure@vulncheck.com)

- https://github.com/mlflow/mlflow/commit/d64cc8b673f71d29d93a7845fc179946ad56a881 (disclosure@vulncheck.com)

- https://github.com/mlflow/mlflow/pull/26842 (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/mlflow-path-traversal-via-trace-id-api (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-53995; retrieved 2026-11-13; source updated 2026-11-13

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53995; retrieved 2026-11-02; source updated 2026-11-02

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-53995; retrieved 2026-11-13; source updated Not reported

Revision: 862093377127c398f0e2e7a66254d6a95c534bd169ce2d4ece24d2f5125b046c

Canonical: https://y2.dev/cve/CVE-2026-53995

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