Security Bulletin
Summary
Langflow contains two authenticated vulnerabilities that allow an attacker to write or delete arbitrary files on the server filesystem accessible to the Langflow process identity. The SaveToFileComponent constructs file paths directly from the attacker-controlled file name field supplied via the tweaks parameter of the run endpoint without any path validation or confinement to the tenant storage directory, allowing an authenticated user to write arbitrary content to any writable path including absolute paths and parent-directory traversals. When Langflow is deployed with S3 storage mode, the file component path resolution skips the local-access confinement check applied by the local storage branch; the delete after processing flag, which defaults to enabled, then invokes local filesystem deletion on the raw attacker-supplied path, enabling authenticated deletion of arbitrary files and directories even when local file access restriction is enabled. Successful exploitation can result in loss of file integrity and availability, deletion of cryptographic key material, and potential follow-on compromise if deleted secrets are replaced under attacker control.
Vulnerability Details
CVEID: CVE-2026-9138
DESCRIPTION: 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.
CWE: CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CVSS Source: IBM
CVSS Base score: 6.5
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N)
CVEID: CVE-2026-19303
DESCRIPTION: Langflow OSS could allow a remote authenticated attacker to delete arbitrary local files or directories due to improper limitation of a pathname to a restricted directory.
CWE: CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CVSS Source: IBM
CVSS Base score: 8.1
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H)
Affected Products and Versions
| Affected Product(s) | Version(s) |
| Langflow OSS | 1.0.0-1.11.2 |
Remediation/Fixes
IBM strongly recommends addressing the vulnerability now by upgrading Langflow OSS to version 1.11.3
Workarounds and Mitigations
None
Get Notified about Future Security Bulletins
References
Acknowledgement
Change History
28 Aug 2026: Initial Publication
*The CVSS Environment Score is customer environment specific and will ultimately impact the Overall CVSS Score. Customers can evaluate the impact of this vulnerability in their environments by accessing the links in the Reference section of this Security Bulletin.
Disclaimer
According to the Forum of Incident Response and Security Teams (FIRST), the Common Vulnerability Scoring System (CVSS) is an "industry open standard designed to convey vulnerability severity and help to determine urgency and priority of response." IBM PROVIDES THE CVSS SCORES ""AS IS"" WITHOUT WARRANTY OF ANY KIND, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. CUSTOMERS ARE RESPONSIBLE FOR ASSESSING THE IMPACT OF ANY ACTUAL OR POTENTIAL SECURITY VULNERABILITY. In addition to other efforts to address potential vulnerabilities, IBM periodically updates the record of components contained in our product offerings. As part of that effort, if IBM identifies previously unidentified packages in a product/service inventory, we address relevant vulnerabilities regardless of CVE date. Inclusion of an older CVEID does not demonstrate that the referenced product has been used by IBM since that date, nor that IBM was aware of a vulnerability as of that date. We are making clients aware of relevant vulnerabilities as we become aware of them. "Affected Products and Versions" referenced in IBM Security Bulletins are intended to be only products and versions that are supported by IBM and have not passed their end-of-support or warranty date. Thus, failure to reference unsupported or extended-support products and versions in this Security Bulletin does not constitute a determination by IBM that they are unaffected by the vulnerability. Reference to one or more unsupported versions in this Security Bulletin shall not create an obligation for IBM to provide fixes for any unsupported or extended-support products or versions.
Document Location
Worldwide
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Document Information
Modified date:
28 August 2026
Initial Publish date:
28 August 2026
UID
ibm17285643