MagicMirror² is an open source modular smart mirror platform. Prior to 2.36.0, an unauthenticated Server-Side Request Forgery (SSRF) vulnerability in the /cors endpoint allows any remote attacker to force the MagicMirror² server to perform arbitrary HTTP requests to internal networks, cloud metadata services, and localhost services. The endpoint also expands environment variable placeholders (**VAR_NAME**), enabling exfiltration of server-side secrets. This vulnerability is fixed in 2.36.0.

Affected: npm: magicmirror

### Summary

An unauthenticated Server-Side Request Forgery (SSRF) vulnerability in the `/cors` endpoint allows any remote attacker to force the MagicMirror² server to perform arbitrary HTTP requests to internal networks, cloud metadata services, and localhost services. The endpoint also expands environment variable placeholders (`**VAR_NAME**`), enabling exfiltration of server-side secrets.

### Details

The `/cors` endpoint in `js/server_functions.js` (function `cors()`, lines 37-78) acts as an open HTTP proxy with no authentication and no URL validation. Any user-supplied URL is fetched server-side via `fetch()` and the full response is returned to the caller.

Additionally, the `replaceSecretPlaceholder()` function (lines 21-25) expands any `**VARIABLE_NAME**` pattern in the URL with the corresponding `process.env` value before the request is made, allowing an attacker to exfiltrate environment variables (e.g. API keys, tokens, database credentials).

**Vulnerable code path:**

``` GET /cors?url=<attacker-controlled-url> → replaceSecretPlaceholder(url) // expands **ENV_VAR** → process.env.ENV_VAR → fetch(url) // no validation, no blocklist → response returned to attacker // full body, status, headers ```

**Key issues:** - No authentication required - No URL validation or blocklist for private/reserved IP ranges - No restriction on URL scheme or destination - Environment variable expansion in URL before fetch

### PoC

**Prerequisites…