# CVE-2026-9138: Path traversal in Langflow OSS

> Authenticated attackers can write or delete arbitrary files via path traversal in Langflow, potentially leading to server compromise.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 4 Sep 2026
- **Updated:** 10 Sep 2026
- **Also known as:** GHSA-44jp-wv2q-qjwp

## What is CVE-2026-9138?

CVE-2026-9138 is a medium-severity path traversal vulnerability in Langflow Langflow, published on 4 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

IBM Langflow OSS 1.0.0 through 1.11.2 Langflow could allow an authenticated attacker to write arbitrary files to the server due to improper input validation in the SaveToFileComponent. The application constructs local file paths using attacker‑controlled input without sufficient sanitization when handling requests to the /api/v1/run/{flow_id} endpoint. An attacker with low‑privileged authenticated access (such as a valid API key or user session) can supply crafted path values, including absolute paths or path traversal sequences, allowing arbitrary file writes to locations writable by the Langflow process. Successful exploitation may lead to unauthorized file creation or modification, potentially resulting in further compromise depending on the deployment environment.

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

## Which versions are affected by CVE-2026-9138?

It affects 1 product.


Products: Langflow Langflow.

## How do I fix CVE-2026-9138?

No fix has been published for CVE-2026-9138 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-9138 being exploited?

There is no known exploitation of CVE-2026-9138 in the wild and no public exploit code.

## Other vulnerabilities in Langflow Langflow

- [CVE-2026-9198](https://insights.sbomify.com/CVE-2026-9198/): IBM Langflow Code Injection (critical 9.8, exploited in the wild)
- [CVE-2026-0770](https://insights.sbomify.com/CVE-2026-0770/): Langflow Inclusion of Functionality from Untrusted Control Sphere (critical 9.8, exploited in the wild)
- [CVE-2025-3248](https://insights.sbomify.com/CVE-2025-3248/): Langflow Missing Authentication (critical 9.8, exploited in the wild)
- [CVE-2025-34291](https://insights.sbomify.com/CVE-2025-34291/): Langflow Origin Validation Error (critical 9.4, exploited in the wild)
- [CVE-2026-33017](https://insights.sbomify.com/CVE-2026-33017/): Langflow Code Injection (critical 9.3, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-9138 and fix it if it is affected.

What it is: CVE-2026-9138 is a medium-severity path traversal vulnerability in Langflow Langflow, published on 4 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-9138 in the wild and no public exploit code.

Affected product: Langflow Langflow. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-9138/ (Markdown: https://insights.sbomify.com/CVE-2026-9138/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-9138
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-9138
- OSV: https://osv.dev/vulnerability/CVE-2026-9138

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-9138/
Summaries are generated and may contain mistakes; the official description above is the record.