D365 F&O MCP Server ships with authentication disabled by default
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-306.
Summary
The dynamics365ninja d365fo-mcp-server package before 1.11.0 has an insecure default in its official Azure one-click deployment. The deployment leaves the API key empty, which disables authentication, and the server listens on all interfaces (CWE-1188). A remote attacker without credentials can read indexed proprietary X++ source, business logic and security-role metadata from the public App Service when the key is left blank and no network restrictions apply.
Written with Claude Haiku 5.5 from the sources below · 2026-10-30
Description from the CNA
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| dynamics365ninja | d365fo-mcp-server | before 1.11.0 | 1.11.0 | Patch available | CNA |
- d365fo-mcp-server Vendordynamics365ninja Affected before 1.11.0 Fixed in 1.11.0 Patch available CNA
Remediation
Upgrade d365fo-mcp-server to version 1.11.0, which fixes this issue. Until the upgrade is applied, configure an API key or network restrictions on the deployment.
Written with Claude Haiku 5.5 from the sources below · 2026-10-30
- Fix · CNA d365fo-mcp-server (dynamics365ninja) Fixed in 1.11.0
Timeline
- 2026-10-21 Threatist record created from CVE-2026-114123
- 2026-10-23 Priority changed: MEDIUM → LOW
- 2026-10-30 CISA SSVC decision points changed
References
Other 4
- https://github.com/dynamics365ninja/d365fo-mcp-server/security/advisories/GHSA-8764-fh3m-wf7g
- https://github.com/dynamics365ninja/d365fo-mcp-server/commit/384394a81e1c6c1e0149586203395240a38fc818
- https://github.com/dynamics365ninja/d365fo-mcp-server/commit/e70bd051f817ebb652d664b10a944fe2c5495de2
- https://github.com/dynamics365ninja/d365fo-mcp-server/releases/tag/v1.11.0
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences