---
id: CVE-2026-5027
title: >-
  The 'POST /api/v2/files' endpoint does not sanitize the 'filename' parameter
  from the multipart form data, allowing an attacker to write files to arbitrary
  locations on the filesystem using path traversal sequences ('../').
summary: >-
  The 'POST /api/v2/files' endpoint does not sanitize the 'filename' parameter
  from the multipart form data, allowing an attacker to write files to arbitrary
  locations on the filesystem using path traversal sequences ('../').
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-22
vendor: langflow
product: langflow
affected:
  - langflow < 1.9.0
patched:
  - langflow 1.9.0
published: '2026-03-27'
updated: '2026-08-18'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-5027'
references:
  - url: 'https://www.tenable.com/security/research/tra-2026-26'
    label: vulnreport@tenable.com
tags:
  - nvd
  - exploit-available
epss: 0.36141
epssPercentile: 0.98408
ingestedAt: '2026-08-18T18:21:28.429Z'
exploitAvailable: true
exploits:
  exploitdb: true
  github: 7
  githubRepos:
    - 'https://github.com/yahiahamza/CVE-2026-5027'
    - 'https://github.com/min8282/CVE-2026-5027'
    - 'https://github.com/EQSTLab/CVE-2026-5027'
  nuclei:
    - CVE-2026-5027
  checkedAt: '2026-09-24T07:53:05.818Z'
---

## Overview

The 'POST /api/v2/files' endpoint does not sanitize the 'filename' parameter from the multipart form data, allowing an attacker to write files to arbitrary locations on the filesystem using path traversal sequences ('../').

## Affected

- `langflow < 1.9.0`

## Remediation

Upgrade past the affected range:

- `langflow 1.9.0`