langflow-ai langflow up to 1.8.x Knowledge Bases API /api/v1/knowledge_bases path traversal

Summaryinfo

A vulnerability has been found in langflow-ai langflow up to 1.8.x and classified as critical. The affected element is an unknown function of the file /api/v1/knowledge_bases of the component Knowledge Bases API. Performing a manipulation results in path traversal. This vulnerability is known as CVE-2026-42867. Remote exploitation of the attack is possible. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as critical has been found in langflow-ai langflow up to 1.8.x. This affects an unknown part of the file /api/v1/knowledge_bases of the component Knowledge Bases API. The manipulation with an unknown input leads to a path traversal vulnerability. CWE is classifying the issue as CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. This is going to have an impact on integrity, and availability. The summary by CVE 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 (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.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-42867 since 04/30/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1006 for this issue.

Upgrading to version 1.9.0 eliminates this vulnerability. Applying a patch is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Artificial Intelligence Software

Vendor

• langflow-ai

Name

• langflow

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8

Website

• Product: https://github.com/langflow-ai/langflow/

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