CVE-2026-9186
Langflow is vulnerable to stored cross-site scripting and IP spoofing due to unsanitized Markdown rendering and untrusted proxy header trust
CVSS Score
6.5
EPSS Score
0.0%
EPSS Percentile
0th
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.).
| CWE | CWE-284 |
| Vendor | ibm |
| Product | langflow oss |
| Published | Sep 4, 2026 |
| Last Updated | Sep 8, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None
Affected Versions
IBM / Langflow OSS
1.0.0 ≤ 1.11.2
Credits
odgrso GMO CyberSecurity by Ierae inc, Edward-x (YLChen-007)