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CVE-2026-42867 langflow-ai CVE debrief

CVE-2026-42867 is a Path Traversal vulnerability in Langflow, a tool for building and deploying AI-powered agents and workflows. The vulnerability exists in the Knowledge Bases API (POST /api/v1/knowledge_bases) due to improper sanitization of user-supplied knowledge base names, allowing an authenticated attacker to create directories and write files anywhere on the server's filesystem. This issue is fixed in Langflow version 1.9.0. The CVSS score for this vulnerability is 6.5, with a severity rating of MEDIUM. Langflow has released a patch and an advisory to address this vulnerability.

Vendor
langflow-ai
Product
langflow
CVSS
MEDIUM 6.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-23
Original CVE updated
2026-06-26
Advisory published
2026-06-23
Advisory updated
2026-06-26

Who should care

Langflow users and administrators should be aware of this vulnerability and take immediate action to update to version 1.9.0 or apply compensating controls. Security teams should prioritize patching and monitoring for potential exploitation attempts. This vulnerability requires authentication, but the potential impact is significant, allowing attackers to manipulate the server's filesystem.

Technical summary

The vulnerability in Langflow's Knowledge Bases API allows an authenticated attacker to perform Path Traversal attacks. This occurs because user-supplied knowledge base names are used directly to create file paths without proper sanitization or containment checks. The CVSS vector for this vulnerability is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L, indicating a Network attack vector with Low complexity and privileges required. The weakness associated with this vulnerability is CWE-22, Improper Limitation of a Pathname to a Restricted Directory.

Defensive priority

Patching to version 1.9.0 is the primary recommended action. In the absence of a patch, defenders should implement compensating controls such as input validation and monitoring for suspicious filesystem activity.

Recommended defensive actions

  • Apply the patch by updating to Langflow version 1.9.0 or later.
  • Implement input validation for knowledge base names to prevent Path Traversal attacks.
  • Monitor for suspicious filesystem activity and adjust logging as necessary.
  • Restrict access to the Knowledge Bases API to only necessary users and services.
  • Perform a thorough inventory of Langflow installations and prioritize patching.

Evidence notes

The CVE record and NVD detail provide official information about the vulnerability. The source item URL provides additional metadata and references. The patch and advisory are available on the Langflow GitHub repository.

Official resources

This article is AI-assisted and based on the supplied source corpus.