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

> Unauthenticated attackers can write arbitrary files outside the intended directory via crafted trace IDs in MLflow's FileStore backend.

- **Severity:** High 8.8 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Oct 2026
- **Updated:** 27 Oct 2026
- **Also known as:** BIT-mlflow-2026-53995, GHSA-wqmh-qccw-pqwf

## What is CVE-2026-53995?

CVE-2026-53995 is a high-severity path traversal vulnerability in mlflow, published on 19 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-53995?

3 open source packages ship an affected version, including mlflow.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `mlflow` | Bitnami | All versions to 3.17.2 | None |
| `mlflow` | PyPI | All versions | 3.17.2 |
| `mlflow` | PyPI | All versions | 3.17.2 |

## How do I fix CVE-2026-53995?

Upgrade mlflow to 3.17.2 or later.

## Is CVE-2026-53995 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-53995 exists.

Public exploit code:

- MLflow <=3.17.1 path traversal allows trace file writes outside the intended directory. (github_poc): https://github.com/SaiTeja-Erukude/CVE-2026-53995-mlflow-path-traversal

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53995 and fix it if it is affected.

What it is: CVE-2026-53995 is a high-severity path traversal vulnerability in mlflow, published on 19 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-53995 exists.

Affected packages and fixed versions:
- mlflow (Bitnami): affected all versions up to 3.17.2; no fix listed
- mlflow (PyPI): affected all versions; fixed in 3.17.2
- mlflow (PyPI): affected all versions; fixed in 3.17.2

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-53995/ (Markdown: https://insights.sbomify.com/CVE-2026-53995/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53995
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53995
- OSV: https://osv.dev/vulnerability/CVE-2026-53995

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53995/
Summaries are generated and may contain mistakes; the official description above is the record.