VULNpocalypse

CVE-2026-114123: D365 F&O MCP Server: Official Azure one-click deployment ships with authentication disabled by default, exposing proprietary X++ source over the public internet

Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.

Generated by VEDAS. Scores as of 2026-11-01 19:19 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.

What it is

D365 F&O MCP Server is a Model Context Protocol server for querying Dynamics 365 Finance & Operations X++ code and metadata. Prior to version 1.11.0, the officially documented Azure one-click deployment uses infrastructure/azuredeploy.json and infrastructure/main.bicep to default the apiKey parameter to an empty string and pass it to the App Service API_KEY setting. With API_KEY unset or empty, src/middleware/apiKeyAuth.ts passes requests through without authentication, while src/index.ts binds the HTTP listener to 0.0.0.0 by default. If the deployer leaves the optional key blank and does not add separate network restrictions or upstream authentication, the resulting public App Service allows unauthenticated JSON-RPC tools/call requests to /mcp. The deployment’s MCP_SERVER_MODE=read-only setting does not prevent anonymous access to read/search tools, including search, get_object_info, batch_get_info, extension_info, security_info, find_references, and find_event_handlers, exposing indexed proprietary X++ source snippets and metadata. Exposed information can include business logic, extension and event-handler wiring, security-role and privilege structure, and labels originally indexed from PackagesLocalDirectory. Deployments protected by a configured API key, effective upstream authentication, or network restrictions preventing attacker access are outside this unauthenticated exposure scenario. This issue is fixed in version 1.11.0.

Description quoted from the CVE record (assigned by GitHub_M, published 2026-10-21).

Weakness: CWE-306: Missing Authentication for Critical Function; CWE-1188: Insecure Default Initialization of Resource

How it can be exploited

Exploitable over the network with low attack complexity needing no privileges and no user interaction. Impact: confidentiality high, integrity none, availability none. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CISA assessment (SSVC): CISA has no evidence of exploitation. Automatable: yes. Technical impact: partial.

Public exploit evidence (Exploit Observer)

VEDAS cluster: VEDAS:DOUBLETROUBLE

Exploit Observer links 2 pieces of public exploit code or detection modules that name this CVE or one of its aliases.

Exploit code and modules (2)

Code that names this CVE. A repository can be a working exploit, a scanner, a fake or malware; read it before running anything.

Vulnerability databases and vendor advisories (1)

Catalogue entries, not exploit evidence.

3 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.

VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.

Live scores

EPSS
0.004
low predicted chance of attack
VEDAS
0.985
strong exploit evidence
On CISA KEV
Not listed
Detection rule
Nuclei

Who is affected

ProductAffectedNot affected
dynamics365ninja d365fo-mcp-serverversion < 1.11.0Not stated

Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.

How to fix it

No fixed version or vendor advisory is listed in the CVE record yet. Watch the vendor’s security page.

How to detect it

Nuclei template (active check)

D365 F&O MCP Server - Unauthenticated JSON-RPC Access

The Dynamics 365 Finance & Operations MCP Server before 1.11.0 ships an Azure one-click deployment that defaults the apiKey parameter to an empty string. With API_KEY unset or empty, src/middleware/apiKeyAuth.ts passes requests through without authentication while the HTTP listener serves the Model Context Protocol JSON-RPC endpoint at /mcp. An unauthenticated attacker can therefore complete the MCP initialize handshake and invoke read/search tools (search, get_object_info, find_event_handlers, security_info, ...), exposing indexed proprietary X++ source, metadata and security-role structure. This template sends an unauthenticated MCP initialize request and confirms the server returns a successful JSON-RPC result with no API key supplied.

Name and description quoted from the template, written by VEDAS.

The template sends 1 request (POST /mcp); it decides using status, word matchers. Severity in the template: high. Marked as not yet verified against a live vulnerable target.

Run it against a host you own or are authorised to test:

bash
nuclei -u https://your-host -t CVE-2026-114123.yaml
Show the template (47 lines)
yaml
id: CVE-2026-114123

info:
  name: "D365 F&O MCP Server - Unauthenticated JSON-RPC Access"
  author: vedas-arpsyndicate
  severity: high
  description: |
    The Dynamics 365 Finance & Operations MCP Server before 1.11.0 ships an Azure one-click deployment that
    defaults the apiKey parameter to an empty string. With API_KEY unset or empty, src/middleware/apiKeyAuth.ts
    passes requests through without authentication while the HTTP listener serves the Model Context Protocol
    JSON-RPC endpoint at /mcp. An unauthenticated attacker can therefore complete the MCP initialize handshake
    and invoke read/search tools (search, get_object_info, find_event_handlers, security_info, ...), exposing
    indexed proprietary X++ source, metadata and security-role structure. This template sends an unauthenticated
    MCP initialize request and confirms the server returns a successful JSON-RPC result with no API key supplied.
  reference:
    - https://www.exploit.observer/?keyword=CVE-2026-114123&match=exact
    - https://subdomain.center/?engine=ammonites&keyword=d365fo-mcp-server&match=exact
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
    cvss-score: 7.5
    cve-id: CVE-2026-114123
    cwe-id: CWE-306
  metadata:
    verified: false
  tags: cve,cve2026,d365fo,mcp,exposure,auth-bypass
http:
  - raw:
      - |
        POST /mcp HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/json
        Accept: application/json, text/event-stream

        {"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-06-18","capabilities":{},"clientInfo":{"name":"vedas","version":"1.0"}}}

    matchers-condition: and
    matchers:
      - type: word
        part: body
        words:
          - '"jsonrpc"'
          - '"result"'
          - '"protocolVersion"'
        condition: and
      - type: status
        status:
          - 200

CVE-2026-114123.yaml on GitHub

References

Other references

Other databases

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, cve-scores (EPSS and VEDAS), Exploit Observer, vedas-signatures. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.