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Vulnerability · Published Oct 21, 2026 · Assigned by GitHub_M

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

High 7.5

In plain English

A high-severity missing authentication in d365fo-mcp-server from dynamics365ninja. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities).

Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.4%top 63.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

VendorProductVersions
dynamics365ninja d365fo-mcp-server < 1.11.0

Weakness: CWE-306, CWE-1188 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

References