---
title: "CVE-2026-42048: Langflow Knowledge Bases API is Vulnerable to Path Traversal"
url: https://erroneo.us/security/cve/CVE-2026-42048/
description: "CVE-2026-42048 (langflow (PyPI)): Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.0, Langflow is vulnerable to…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-05-12
date_modified: 2026-05-13
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-42048"
kev: false
cvss: 9.6
epss: 0.00601
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-42048: Langflow Knowledge Bases API is Vulnerable to Path Traversal

**Signal:** Critical, preconditions apply. Severe if exploited, but exploitation needs conditions that may not apply to you. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.6% , percentile 48: FIRST’s model estimates a 0.6% chance of exploitation activity in the next 30 days, higher than 48% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Needs an account (low (any account)). Exposure depends on who can log in.
- Only applies if your dependency tree includes langflow (PyPI) <= 1.8.4, fixed in 1.9.0 . Check your lockfile, including transitive dependencies.

## What it is

Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.0, Langflow is vulnerable to Path Traversal in the Knowledge Bases API (DELETE /api/v1/knowledgebases). This occurs because user-supplied knowledge base names are concatenated directly into file paths without proper sanitization or boundary validation. An authenticated attacker can exploit this flaw to delete arbitrary directories anywhere on the server's filesystem, leading to data loss and potential service disruption. This vulnerability is fixed in 1.9.0.

## Affected packages

- PyPI `langflow` <= 1.8.4 → fixed: 1.9.0

## Affected products (CVE record)

- langflow-ai langflow: < 1.9.0

## Severity

- GitHub_M CVSS 3.1: 9.6 `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H`
- GitHub CVSS 3.1: 9.6 `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable no , technical impact partial .
- FIRST EPSS (model of 2026-10-21): 0.60% probability of exploitation activity in the next 30 days; percentile 48.

## Sources

- [GitHub Advisory GHSA-9whx-c884-c68q](https://github.com/advisories/GHSA-9whx-c884-c68q)
- [CVE.org record CVE-2026-42048](https://www.cve.org/CVERecord?id=CVE-2026-42048)
- [NVD entry CVE-2026-42048](https://nvd.nist.gov/vuln/detail/CVE-2026-42048)
- [github.com](https://github.com/langflow-ai/langflow/security/advisories/GHSA-9whx-c884-c68q)

---
Source page: https://erroneo.us/security/cve/CVE-2026-42048/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt