Langflow: IBM Langflow OSS 1.0.0 through 1.10.0 Langflow could allow an attacker to write arbitrary files…
Langflow
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- Severity
- Critical, CVSS 9.9
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- Record
- CVE-2026-8859
- Affects
- Langflow
- Known exploited
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Published
- Record first published by the source
- July 17, 2026
- Source last modified
- October 24, 2026
Description
IBM Langflow OSS 1.0.0 through 1.10.0 Langflow could allow an attacker to write arbitrary files to unintended locations due to improper input validation in the APIRequest component. A path traversal vulnerability exists when the "Save to File" feature is enabled, where filenames extracted from HTTP response Content-Disposition headers are not sanitized before being joined to the temporary directory path. An attacker controlling an external HTTP server can supply crafted filename values containing path traversal sequences (e.g., ../), enabling arbitrary file writes to locations accessible by the Langflow process.
Description quoted from the NVD record.
Who is affected
Langflow (also called IBM Langflow OSS) is a tool for building apps that use AI language models. This flaw affects versions 1.0.0 through 1.10.0. The problem is in a building block that lets a workflow contact other web services. It matters when that building block's "Save to File" feature is turned on. Someone who controls an outside web server that your workflow contacts could send back a specially crafted file name. Langflow would then write files to unintended places on the computer it runs on, anywhere Langflow itself is allowed to write. This flaw is rated Critical.
What to do
- If someone in your organization installed and runs Langflow, that person should act on this advisory. If an IT provider or vendor runs it for you, send them this advisory and ask when the update will be done.
- Check which version of Langflow you use. Versions 1.0.0 through 1.10.0 have this flaw.
- No fixed version is named for this flaw yet, so check the vendor advisory linked on this page for a fixed release and install it as soon as one is available.
- Until then, find out whether any of your workflows use the building block that contacts other web services with its "Save to File" feature turned on, since that is the setup this flaw affects.
Analysis written from the source record as of October 24, 2026 and reviewed before publishing.