Vulnerability · Published Jun 23, 2026 · Assigned by GitHub_M

CVE-2026-42867Langflow: Path Traversal in Knowledge Bases API via Creation Endpoint

Medium 6.5

In plain English

A medium-severity path traversal in langflow from langflow-ai. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 41% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.5Medium

Exploit odds (30 days)0.5%top 59.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

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 (POST /api/v1/knowledge_bases). This occurs because user-supplied knowledge base names are used directly to create file paths without proper sanitization or containment checks. An authenticated attacker can exploit this flaw to create directories and write files anywhere on the server's filesystem. This vulnerability is fixed in 1.9.0.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
PyPI	langflow	1.9.0	GHSA-79ph-745m-6wxq
PyPI	langflow	1.9.0	PYSEC-2026-2566

Affected products (as reported)

Vendor	Product	Versions
langflow-ai	langflow	< 1.9.0

Weakness: CWE-22 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

References

https://github.com/langflow-ai/langflow/security/advisories/GHSA-79ph-745m-6wxq x_refsource_CONFIRM
https://github.com/langflow-ai/langflow/pull/12337 x_refsource_MISC