IBM Langflow OSS 1.0.0 through 1.11.2 allows remote authenticated attackers to bypass localhost-only MCP configuration installation by spoofing X-Forwarded-For: 127.0.0.1 header, enabling arbitrary writes to IDE config files (~/.cursor/mcp.json, etc.).

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Advisories

No advisories yet.

Fixes

Solution

IBM strongly recommends addressing the vulnerability now by upgrading Langflow OSS to version 1.11.3 https://pypi.org/project/langflow/


Workaround

No workaround given by the vendor.

History

Fri, 04 Sep 2026 14:45:00 +0000

Type Values Removed Values Added
Description IBM Langflow OSS 1.0.0 through 1.11.2 allows remote authenticated attackers to bypass localhost-only MCP configuration installation by spoofing X-Forwarded-For: 127.0.0.1 header, enabling arbitrary writes to IDE config files (~/.cursor/mcp.json, etc.).
Title Langflow is vulnerable to stored cross-site scripting and IP spoofing due to unsanitized Markdown rendering and untrusted proxy header trust
First Time appeared Ibm
Ibm langflow Oss
Weaknesses CWE-284
CPEs cpe:2.3:a:ibm:langflow_oss:1.0.0:*:*:*:*:*:*:*
cpe:2.3:a:ibm:langflow_oss:1.11.2:*:*:*:*:*:*:*
Vendors & Products Ibm
Ibm langflow Oss
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: ibm

Published:

Updated: 2026-09-04T14:23:20.117Z

Reserved: 2026-05-21T14:59:59.486Z

Link: CVE-2026-9186

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-04T15:17:50.860

Modified: 2026-09-04T15:17:50.860

Link: CVE-2026-9186

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-04T16:30:06Z

Weaknesses