Read the docs
TI-2026-68343 Aliases CVE-2026-105699GHSA-4hmc-cfm3-w43c

Authorization bypass in Langflow MCP resource handlers exposes files

Priority MEDIUM 64CWE-639Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Security bypass
Confidentiality · integrity · availability
High · None · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-639.

Summary

Langflow from 1.6.8 before 1.9.1 does not verify that a resource URI read through MCP belongs to the authenticated user's project, an authorization bypass (CWE-639). An authenticated user with access to any project-scoped MCP endpoint can read other users' private flow files, such as uploaded documents and prompts.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

Langflow is a tool for building and deploying AI-powered agents and workflows. From 1.6.8 until 1.9.1, Langflow authenticated access to the project identifier in a project-scoped MCP connection but did not authorize the resource URI supplied to resources/read. read_resource forwarded the attacker-controlled URI to handle_read_resource, which parsed a flow_id and filename and called storage_service.get_file without verifying that the flow belonged to the authenticated user or current project. A user with access to any project-scoped MCP endpoint could therefore request another user's flow-backed file, while global handle_list_resources and handle_list_tools behavior could disclose flow and file identifiers that made targeting easier. The vulnerability disclosed uploaded documents, structured data, prompts, and other private flow artifacts across tenants but did not modify victim files or stored flows. This issue is fixed in version 1.9.1.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00412 35th percentileScored 2026-11-07
Fix Fixed langflow (PyPI): 1.9.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Langflowlangflow1.6.8 – 1.9.0—No fix listedCNA
—langflow (PyPI)1.6.8 to before 1.9.11.9.1Patch availableGHSA-4hmc-cfm3-w43c
  • langflow VendorLangflow Affected 1.6.8 – 1.9.0 Fixed in — No fix listed CNA
  • langflow (PyPI) Vendor— Affected 1.6.8 to before 1.9.1 Fixed in 1.9.1 Patch available GHSA-4hmc-cfm3-w43c

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:langflow:langflow:*:*:*:*:*:*:*:*——Langflow
  • cpe:2.3:a:langflow:langflow:*:*:*:*:*:*:*:* Versions — — ·Langflow

Remediation

Upgrade Langflow to version 1.9.1, which fixes this issue.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

  • Fix · GHSA-4hmc-cfm3-w43c langflow (PyPI) Fixed in 1.9.1 Advisory →

Timeline

  1. 2026-10-06 Threatist record created from CVE-2026-105699
  2. 2026-10-07 Priority changed: MEDIUM → LOW
  3. 2026-10-07 Alias added: GHSA-4hmc-cfm3-w43c
  4. 2026-10-07 Fix available: PyPI/[email protected] · GHSA-4hmc-cfm3-w43c
  5. 2026-10-07 CVSS score added · GHSA-4hmc-cfm3-w43c
  6. 2026-10-07 Weakness changed · GHSA-4hmc-cfm3-w43c
  7. 2026-10-07 7 new references · GHSA-4hmc-cfm3-w43c
  8. 2026-10-08 CISA SSVC decision points changed
  9. 2026-10-08 Priority changed: LOW → MEDIUM

References

Advisory 1

Other 6

  • TI-2026-08085 Unauthenticated Remote Code Execution via Auto-Login Bypass and Code Validation KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-00553 Langflow exec_globals Inclusion of Functionality from Untrusted Control Sphere Remote… KEVCVSS 3.0CRITICAL 9.8
  • TI-2025-24427 Langflow <= 1.6.9 CORS Misconfiguration to Token Hijack & RCE KEVCVSS 4.0CRITICAL 9.4
  • TI-2025-02845 Langflow < 1.3.0 Unauthenticated RCE via /api/v1/validate/code KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-25463 Langflow has Unauthenticated Remote Code Execution via Public Flow Build Endpoint KEVCVSS 4.0CRITICAL 9.3
  • TI-2026-39928 Authorization bypass in langflow KEVCVSS 3.1HIGH 8.4
See all 236 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences