Security Bulletin
Summary
Langflow OSS contains a critical vulnerability in code validate endpoint due to unsafe use of Python's exec() function within the validate_code routine. While the feature is intended to validate user-supplied function definitions, it fails to account for Python decorators, which are executed at definition time. An authenticated attacker can exploit this by submitting a crafted payload with a malicious decorator, triggering arbitrary code execution during validation. This allows execution of system commands with the privileges of the Langflow process, leading to full remote code execution (RCE) and potential system compromise. Now users have to consent to this code execution feature
Vulnerability Details
CVEID: CVE-2026-6543
DESCRIPTION: Langflow allows an attacker to execute arbitrary commands with the privileges of the process running Langflow. This allows reading sensitive environment variables (API keys, DB credentials), modifying files, or launching further attacks on the internal network.
CWE: CWE-94: Improper Control of Generation of Code ('Code Injection')
CVSS Source: IBM
CVSS Base score: 8.8
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
Affected Products and Versions
| Affected Product(s) | Version(s) |
| Langflow OSS | 1.0.0 - 1.8.4 |
Remediation/Fixes
IBM recommends addressing the vulnerability now by upgrading to Langflow OSS 1.9.0 or newer: https://github.com/langflow-ai/langflow
Workarounds and Mitigations
None
Get Notified about Future Security Bulletins
References
Acknowledgement
Eran Shimony (Palo Alto Networks)
Change History
27 Apr 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:
27 April 2026
Initial Publish date:
27 April 2026
UID
ibm17270883