CVE-2026-9138
Received Received - Intake

Authenticated File Write Vulnerability in IBM Langflow OSS

Publication date: 2026-09-04

Last updated on: 2026-09-04

Assigner: IBM Corporation

Description
IBM Langflow OSS 1.0.0 through 1.11.2 Langflow could allow an authenticated attacker to write arbitrary files to the server due to improper input validation in the SaveToFileComponent. The application constructs local file paths using attacker‑controlled input without sufficient sanitization when handling requests to the /api/v1/run/{flow_id} endpoint. An attacker with low‑privileged authenticated access (such as a valid API key or user session) can supply crafted path values, including absolute paths or path traversal sequences, allowing arbitrary file writes to locations writable by the Langflow process. Successful exploitation may lead to unauthorized file creation or modification, potentially resulting in further compromise depending on the deployment environment.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-09-04
Last Modified
2026-09-04
Generated
2026-09-04
AI Q&A
2026-09-04
EPSS Evaluated
N/A
NVD
CVE-2026-9138
EUVD
EUVD-2026-71217

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
ibm langflow From 1.0.0 (inc) to 1.11.2 (inc)

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
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.

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

This vulnerability is an arbitrary file write issue in IBM Langflow OSS versions 1.0.0 through 1.11.2. It occurs because the application does not properly validate user input when saving files. An authenticated attacker can manipulate file paths to write files to arbitrary locations on the server by sending crafted requests to the /api/v1/run/{flow_id} endpoint.

Detection Guidance

Detecting this vulnerability requires checking for unauthorized file writes in the Langflow application. Monitor logs for suspicious requests to /api/v1/run/{flow_id} with crafted path values. Review file system changes in directories writable by the Langflow process. No specific commands are provided in the context.

Impact Analysis

This vulnerability allows an attacker with low-privileged access to create or modify files on the server. This could lead to unauthorized code execution, data corruption, or further attacks depending on the server's configuration and the files targeted.

Compliance Impact

This vulnerability could lead to unauthorized file writes or deletions, potentially exposing or destroying sensitive data such as personal information or protected health records. Compliance with GDPR or HIPAA may be impacted if such data is compromised or lost due to file manipulation.

Mitigation Strategies

Upgrade IBM Langflow OSS to a version beyond 1.11.2. Implement strict input validation for file paths in the SaveToFileComponent. Restrict write permissions for the Langflow process to only necessary directories. Apply network-level controls to limit access to the /api/v1/run/{flow_id} endpoint.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-9138. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart