MediumVulnerability

CVE-2026-9186: IBM Langflow OSS MCP configuration bypass via spoofed X-Forwarded-For header

Source: NVD(opens in a new tab)
Identifier: CVE-2026-9186
Published: September 4, 2026
Record updated: October 9, 2026

Known exploitation: Not listed in the CISA Known Exploited Vulnerabilities catalog at the last check.
EPSS: 0.4%

Summary

IBM Langflow OSS versions 1.0.0 through 1.11.2 contain a flaw tracked as CVE-2026-9186. Remote authenticated attackers can bypass the localhost-only restriction on MCP configuration installation by spoofing the X-Forwarded-For: 127.0.0.1 header. This allows arbitrary writes to IDE configuration files such as ~/.cursor/mcp.json.

Mitigation

The source does not state a fix yet. Check the original advisory for updates.

Details

Scores and exploitation

CVSS score: 6.5(medium)
CVSS vector: 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
EPSS: 0.4%Estimated probability that this CVE is exploited in the next 30 days, from the FIRST Exploit Prediction Scoring System. Read on November 4, 2026.
Disclosure date: September 4, 2026

Weaknesses and techniques

Weakness (CWE): CWE-284

Classification

Attack type: Other
Attack sophistication: Moderate
AI component targeted: Plugin
Impact: Integrity
Labels: security

How this record was produced

Summaries, mitigations and labels on this page are generated automatically from the source. The linked source is authoritative. The source gives this advisory a description and no title, so the title above is a headline generated from the source text.

Original source: https://nvd.nist.gov/vuln/detail/CVE-2026-9186

First tracked: September 4, 2026 at 02:08 PM ET, from NVD/CVE Database

Classifier: claude-haiku-5-5, prompt v4

Classifier confidence: 90% (self-assessed)

Topics

Model Context Protocol

Summary

Mitigation

Topics

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