Executive brief
IBM Langflow is a visual development tool for building AI workflows and applications. An authenticated user can exploit insufficient input validation in the file-saving feature to write arbitrary files anywhere on the server. This could lead to unauthorized data modification, service disruption, or system compromise depending on what permissions the Langflow process has.
Technical details
The vulnerability is a path traversal (CWE-22) flaw in the SaveToFileComponent of Langflow OSS. The application constructs local file paths directly from attacker-controlled input via the tweaks parameter in the /api/v1/run/{flow_id} endpoint without proper path validation or confinement. An authenticated attacker with low privileges (API key or user session) can supply absolute paths or path traversal sequences (e.g., ../../../etc/passwd) to write files to any location writable by the Langflow process. Successful exploitation enables unauthorized file creation and modification, potentially leading to follow-on compromise such as secret injection or configuration tampering. The vulnerability affects Langflow OSS versions 1.0.0 through 1.11.2; IBM recommends upgrading to version 1.11.3 or later.
Affected products
- IBM Langflow OSS 1.0.0 through 1.11.2
Timeline
- 2026-09-04: disclosed
- 2026-08-28: patched: IBM Security Bulletin published on 28 Aug 2026; upgrade to version 1.11.3 recommended