IBM Langflow OSS 1.0.0 through 1.12.4 contains three message endpoints that perform no ownership verification. Any authenticated user can bulk-delete another user's messages, overwrite message content to inject malicious prompts, or hijack an entire conversation session by reassigning its session ID.
Advisories

No advisories yet.

Fixes

Solution

IBM strongly recommends addressing the vulnerability now by upgrading Langflow OSS to version 1.12.5. https://pypi.org/project/langflow/1.12.5/ For Langflow OSS versions 1.0.0 - 1.12.4, follow the Prepare to upgrade instructions and release-specific configuration changes https://docs.langflow.org/release-notes , including backing up your existing installation, then follow the Langflow OSS installation instructions https://docs.langflow.org/get-started-installation to install version 1.12.5 and test your flows. For deployments using MCP stdio, also apply the configuration controls in Workarounds and Mitigations. This bulletin also discloses fixes delivered in prior releases: CVE-2026-107366 was fixed in version 1.9.0; CVE-2026-18894 was fixed in version 1.11.2; and CVE-2026-77817 was fixed in version 1.11.5. Version 1.12.5 includes these fixes.


Workaround

IBM strongly recommends applying the following configuration controls to deployments using MCP stdio in addition to upgrading Langflow OSS to version 1.12.5. These controls do not replace the upgrade. Set LANGFLOW_MCP_SERVER_INTERPRETER_HARDENING=true to reject direct shell-script execution, and set LANGFLOW_CUSTOM_COMPONENT_ADMIN_ONLY=true to block non-admin MCP stdio access. Restart the Langflow service after updating its environment configuration. These restrictions can require changes to existing MCP server launch configurations and limit which users can use MCP stdio. For public workflows, retain the default restriction on custom components. Explicitly enabling LANGFLOW_ALLOW_PUBLIC_CUSTOM_COMPONENTS permits custom component execution and changes the default protection described for CVE-2026-18894. For CVE-2026-77817, upgrading prevents the identified secret disclosure in new flow and project exports. Revoke or rotate any credentials exposed in previously exported files; upgrading does not remove secrets from copies already exported.

History

Tue, 20 Oct 2026 00:00:00 +0000

Type Values Removed Values Added
Description IBM Langflow OSS 1.0.0 through 1.12.4 contains three message endpoints that perform no ownership verification. Any authenticated user can bulk-delete another user's messages, overwrite message content to inject malicious prompts, or hijack an entire conversation session by reassigning its session ID.
Title Langflow OSS Authorization Bypass Through User-Controlled Key
First Time appeared Ibm
Ibm langflow Oss
Weaknesses CWE-639
CPEs cpe:2.3:a:ibm:langflow_oss:1.0.0:*:*:*:*:*:*:*
cpe:2.3:a:ibm:langflow_oss:1.12.4:*:*:*:*:*:*:*
Vendors & Products Ibm
Ibm langflow Oss
References
Metrics cvssV3_1

{'score': 8.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: ibm

Published:

Updated: 2026-10-19T23:49:23.120Z

Reserved: 2026-10-07T20:49:16.611Z

Link: CVE-2026-107366

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-20T00:17:25.640

Modified: 2026-10-20T00:17:25.640

Link: CVE-2026-107366

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses