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Security Bulletin: Unauthenticated Remote Code Execution via Auto-Login Bypass and Code Validation

Security Bulletin


Summary

A vulnerability allowed unauthenticated attackers to achieve remote code execution on default-configured instances. The vulnerability combined two distinct issues: an unauthenticated endpoint that issued superuser bearer tokens to any network caller, and a code validation endpoint that executed arbitrary Python code. An attacker could chain these vulnerabilities by first obtaining a superuser token from the auto-login endpoint, then using that token to submit malicious code to the validation endpoint. The code validator executed Python decorators, default arguments, and annotations at function definition time, enabling arbitrary command execution on the host system. This affected all default deployments where the auto-login feature was enabled and the validation endpoint was network-accessible.

Vulnerability Details

CVEID:   CVE-2026-9198
DESCRIPTION:   Langflow OSS allows unauthenticated attackers to chain /api/v1/auto_login (mints SUPERUSER tokens to any network caller) with /api/v1/validate/code (executes user code via exec()) to achieve full RCE on default Langflow deployments
CWE:   CWE-94: Improper Control of Generation of Code ('Code Injection')
CVSS Source:   IBM
CVSS Base score:   9.8
CVSS Vector:   (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)

Affected Products and Versions

Affected Product(s)Version(s)
Langflow OSS1.0.0-1.10.0

Remediation/Fixes

IBM strongly recommends addressing the vulnerability now by upgrading Langflow OSS to version 1.10.1

Workarounds and Mitigations

None

Get Notified about Future Security Bulletins

References

Off

Acknowledgement

Change History

02 Jul 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:
02 July 2026

Initial Publish date:
02 July 2026

UID

ibm17278927