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Findings

CVE-2026-105699

Langflow has Authenticated Cross-Project File Disclosure via Unscoped MCP Resource Handlers

Published Oct 7, 2026 · corrected/updated Oct 15, 2026 · evidence confidence high

### Summary Langflow's project-scoped MCP transport authenticates the caller for the in the connection URL, but the subsequent operation does not authorize the resource URI being requested. An authenticated user can connect to their own project-scoped MCP endpoint and supply a crafted file-download URI that points to another user's flow-backed file. The server then reads and returns the victim file without verifying ownership or project membership. This is a cross-user authorization bypass ( ) that allows arbitrary read access to files stored under other users' flow namespaces. ### Details Verified against local checkout: - Repository: - Verified on release tag: - Commit: - Earliest stable release known to contain the vulnerable code path: Relevant code path: 1. authenticates the caller and checks access only to the in the MCP transport URL. 2. The project-scoped MCP server registers and forwards the attacker-controlled URI directly to . 3. parses the last two URI path segments as and , then directly calls: No check ties the supplied back to the authenticated user or the current project. 4. The storage layer performs a raw namespace read and is not authorization-aware. The result is that authorization is enforced at MCP connection time, but not at resource-read time. Once an attacker has access to any project-scoped MCP endpoint they own, they can read another user's flow-backed file by passing a victim-controlled URI. This issue is also easier to exploit because the global MCP helpers expose cross-user discovery data: - lists files for all flows. - queries all flows and includes flow IDs in tool metadata. That global enumeration is not required for exploitation, but it makes obtaining victim identifiers much easier. ### PoC Preconditions: - Langflow is running locally with authentication enabled. - Two separate users exist on the same instance. - The victim has a flow with an uploaded file. - The attacker has access to any project they own. Verify the issue locally

Grounded briefings

Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.

Executive

CVE-2026-105699 is a high public vulnerability record for this product. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.

System administrator

Identify whether this product is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: langflow (1.6.8 → 1.9.1). Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.

Security analyst

Signals on file: EPSS 0.2%. It is not currently listed in the CISA Known Exploited catalog. Weakness classes: CWE-639. Sources contributing to this record: cve_org, epss, github, osv. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.

Exploitation and remediation

  • Exploitation evidence

    Not listed as known exploited in CISA KEV. Not in CISA KEV or VulnCheck KEV.

  • Patch and remediation

    No required-action text is stored yet. Use the vendor or CERT links in Sources for patch availability.

  • Safe detection guidance

    Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 7, 2026 · GitHub Advisory Database

    Detected

    ### Summary Langflow's project-scoped MCP transport authenticates the caller for the in the connection URL, but the subsequent operation does not authorize the resource URI being requested. An authenticated user can connect to their own project-scoped MCP endpoint and supply a crafted file-download URI that points to another user's flow-backed file. The server then reads and returns the victim fil

  2. Oct 15, 2026 · GitHub Advisory Database

    Fix available

    langflow fixed in 1.9.1

  3. Oct 15, 2026 · GitHub Advisory Database

    Fix available

    langflow fixed in 1.9.1

  4. Oct 15, 2026 · GitHub Advisory Database

    Updated

    ### Summary Langflow's project-scoped MCP transport authenticates the caller for the in the connection URL, but the subsequent operation does not authorize the resource URI being requested. An authenticated user can connect to their own project-scoped MCP endpoint and supply a crafted file-download URI that points to another user's flow-backed file. The server then reads and returns the victim fil

Affected

  • PyPI langflow1.6.8 → 1.9.1

Sources

References