Is CVE-2026-42867 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-42867 being exploited in the wild.

How severe is CVE-2026-42867?

Medium severity, with a CVSS score of 6.5, published 23 June 2026.

Which products and versions are affected?

langflow (PyPI) ECOSYSTEM:introduced=0,fixed=1.9.0.

Is there a fix for CVE-2026-42867?

Yes. langflow (PyPI): upgrade to 1.9.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-42867 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-42867?

Check whether you run langflow (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-42867: Langflow path traversal in Knowledge Bases API

CVE-2026-42867 · Severity: medium · CVSS 6.5 · Published 2026-06-23

Langflow is a platform used to build and deploy AI-powered workflows and agents. A security flaw in its Knowledge Bases component allows users to bypass folder restrictions by providing specially crafted names. This could allow an attacker to create unauthorized folders or overwrite specific configuration files elsewhere on the server, potentially leading to data corruption or interference with other users' work.

Technologies: langflow (PyPI). Vendors: PyPI.

Quick answers

Is CVE-2026-42867 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-42867 being exploited in the wild.
How severe is CVE-2026-42867?: Medium severity, with a CVSS score of 6.5, published 23 June 2026.
Which products and versions are affected?: langflow (PyPI) ECOSYSTEM:introduced=0,fixed=1.9.0.
Is there a fix for CVE-2026-42867?: Yes. langflow (PyPI): upgrade to 1.9.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-42867 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-42867?: Check whether you run langflow (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

langflow (PyPI): upgrade to 1.9.0 or later
```
pip install "langflow>=1.9.0"
```

Technical details

A path traversal vulnerability exists in the `create_knowledge_base` function within `src/backend/base/langflow/api/v1/knowledge_bases.py`. The `POST /api/v1/knowledge_bases` endpoint fails to sanitize the user-supplied `name` field before using it to construct file paths via `kb_path.mkdir()`. An attacker can use traversal sequences (e.g., `../`) or absolute paths to create directories and write application-specific files (`embedding_metadata.json` and `schema.json`) outside the intended root directory. This can result in cross-user data compromise or arbitrary filesystem manipulation. The issue is resolved in version 1.9.0 by implementing strict path validation using `Path.is_relative_to()`.

Affected products

langflow-ai Langflow < 1.9.0

Identifiers

CVE-2026-42867
GHSA-79ph-745m-6wxq
PYSEC-2026-2566

Timeline

2026-03-26: patched: Fix merged into release-1.9.0 branch
2026-06-11: advisory: GitHub Security Advisory published
2026-06-23: disclosed: CVE published to NVD

References

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