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.
Published: 2026-09-04
Score: 6.5 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

The vulnerability is a path validation flaw in the SaveToFileComponent of IBM Langflow OSS, allowing an authenticated user to supply crafted file paths to the /api/v1/run/{flow_id} endpoint. Attackers can construct absolute or traversal sequences, resulting in arbitrary files being written or deleted on the server. This could enable the creation of malicious scripts, overwrite configuration files, or otherwise compromise the application or host. The flaw is classified as CWE‑22.

Affected Systems

IBM Langflow OSS versions 1.0.0 through 1.11.2 are affected. The vulnerable component is present in all releases in this range. Upgrading to 1.11.3 removes the flaw.

Risk and Exploitability

The CVSS score of 6.5 indicates moderate severity. Exploitation requires authenticated access, which is typically granted with an API key or user session, so the attack vector is remote via API calls. The EPSS score is not available, and the vulnerability is not listed in CISA's KEV catalog. While the flaw does not allow arbitrary code execution directly, the ability to write arbitrary files can lead to further exploitation depending on the environment and file system permissions.

Generated by OpenCVE AI on September 4, 2026 at 15:54 UTC.

Remediation

Vendor Solution

IBM strongly recommends addressing the vulnerability now by upgrading Langflow OSS to version 1.11.3 https://pypi.org/project/langflow/

OpenCVE Recommended Actions

  • Upgrade IBM Langflow OSS to version 1.11.3 or later to remove the path validation bug.
  • If an upgrade is not immediately possible, limit the scope of API keys so that only trusted users can invoke the /api/v1/run endpoint.
  • Implement or patch the SaveToFileComponent to reject file paths containing absolute references or traversal sequences and enforce strict whitelisting of allowed directories.

Generated by OpenCVE AI on September 4, 2026 at 15:54 UTC.

Tracking

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Advisories

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History

Fri, 04 Sep 2026 14:45:00 +0000

Type Values Removed Values Added
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.
Title Langflow is vulnerable to arbitrary file write and arbitrary file deletion due to unvalidated paths in file-processing components
First Time appeared Ibm
Ibm langflow Oss
Weaknesses CWE-22
CPEs cpe:2.3:a:ibm:langflow_oss:1.0.0:*:*:*:*:*:*:*
cpe:2.3:a:ibm:langflow_oss:1.11.2:*:*:*:*:*:*:*
Vendors & Products Ibm
Ibm langflow Oss
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N'}

Subscriptions

Ibm Langflow Oss
cve-icon MITRE

Status: PUBLISHED

Assigner: ibm

Published:

Updated: 2026-09-04T14:27:27.568Z

Reserved: 2026-05-20T18:55:09.275Z

Link: CVE-2026-9138

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-04T15:17:50.717

Modified: 2026-09-04T15:17:50.717

Link: CVE-2026-9138

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-04T16:15:05Z

Weaknesses
  • CWE-22

    Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')