CVE-2026-6599: Langflow Langflow Vulnerable To Injection Vulnerability

LOW
Advisory Identifier: GHSA-v66p-f7x3-4794
Share
CVSS 6.3
CWE-74
Published
Advisory Summary

CVE-2026-6599 is a LOW (CVSS 6.3) langflow vulnerable to injection vulnerability (CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')) affecting Langflow libraries in the PyPI ecosystem. The issue involves langflow vulnerable to injection. Remediation is available in the latest vendor maintenance releases.

CVE-2026-6599 at a Glance

CVE Identifier CVE-2026-6599
GHSA Identifier GHSA-v66p-f7x3-4794
Severity LOW
CVSS v3.1 Base Score 6.3
CWE Classification CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
Affected Product Langflow
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 6.3

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality Low (C:L)
Integrity Low (I:L)
Availability Low (A:L)

How to Fix CVE-2026-6599

To remediate this vulnerability, upgrade all affected Langflow dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

langflow fixed: Latest secure release 
pip install langflow>=Latest secure release
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show langflow

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2026-6599, inspect your installed packages using pip:

pip show langflow

Analyze the terminal output to locate any version of Langflow in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The pip show langflow command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection'), where the product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component. In Langflow, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

A vulnerability was detected in langflow-ai langflow up to 1.8.3. The impacted element is the function get_client_ip/install_mcp_config of the file src/backend/base/langflow/api/v1/mcp_projects.py of the component Model Context Protocol Configuration API. Performing a manipulation of the argument X-Forwarded-For results in injection. The attack may be initiated remotely. The exploit is now public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

CVE-2026-6599 Affected Langflow Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
langflow
pypi/langflow
PyPI
≤ 1.8.3

References

NVD — CVE-2026-6599 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-6599
Langflow Source Repository REPOSITORY
https://gist.github.com/chenhouser2025/a909c47316b7a0948ee68c109ab747a3
Langflow Source Repository REPOSITORY
https://github.com/langflow-ai/langflow
vuldb.com/submit/791922 WEB
https://vuldb.com/submit/791922
vuldb.com/vuln/358234 WEB
https://vuldb.com/vuln/358234
vuldb.com/vuln/358234/cti WEB
https://vuldb.com/vuln/358234/cti

Frequently Asked Questions

What is CVE-2026-6599?
CVE-2026-6599 is a security vulnerability in Langflow involving Langflow vulnerable to injection under CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection').
Which Langflow versions are affected?
Affected versions include releases prior to current release patches across affected packages: langflow.
What version fixes CVE-2026-6599?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is langflow affected?
Yes, langflow is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2026-6599?
CVE-2026-6599 has a CVSS v3.1 base score of 6.3 (LOW) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L.
What CWE is associated with CVE-2026-6599?
CVE-2026-6599 is classified under CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') (The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.).
How can I check PyPI dependencies for CVE-2026-6599?
Run the dependency tree command: 'pip show langflow'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-v66p-f7x3-4794",
  "modified" : "2026-04-28T23:18:33Z",
  "published" : "2026-04-20T06:31:27Z",
  "aliases" : [ "CVE-2026-6599" ],
  "summary" : "Langflow vulnerable to injection",
  "details" : "A vulnerability was detected in langflow-ai langflow up to 1.8.3. The impacted element is the function get_client_ip/install_mcp_config of the file src/backend/base/langflow/api/v1/mcp_projects.py of the component Model Context Protocol Configuration API. Performing a manipulation of the argument X-Forwarded-For results in injection. The attack may be initiated remotely. The exploit is now public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "langflow"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "1.8.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-6599"
  }, {
    "type" : "WEB",
    "url" : "https://gist.github.com/chenhouser2025/a909c47316b7a0948ee68c109ab747a3"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/langflow-ai/langflow"
  }, {
    "type" : "WEB",
    "url" : "https://vuldb.com/submit/791922"
  }, {
    "type" : "WEB",
    "url" : "https://vuldb.com/vuln/358234"
  }, {
    "type" : "WEB",
    "url" : "https://vuldb.com/vuln/358234/cti"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-74" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-28T23:18:33Z",
    "nvd_published_at" : "2026-04-20T04:16:53Z"
  }
}