authelia/authelia · critical · Error

No ${variableName} embedded variable detected

Error message

No ${variableName} embedded variable detected

What it means

getEmbeddedVariable reads data-{name} attributes that Authelia's backend injects into the <body> tag of the templated index.html (e.g. data-duoselfenrollment, data-logooverride, data-theme, data-rememberme, data-resetpassword). The throw means the attribute is absent, i.e. the HTML was not rendered by Authelia's server-side template. This usually breaks the portal at bootstrap, since these flags drive first-factor options and theming.

Source

Thrown at web/src/utils/Configuration.ts:4

export function getEmbeddedVariable(variableName: string) {
    const value = document.body.getAttribute(`data-${variableName}`);
    if (value === null) {
        throw new Error(`No ${variableName} embedded variable detected`);
    }

    return value;
}

export function getDuoSelfEnrollment() {
    return getEmbeddedVariable("duoselfenrollment") === "true";
}

export function getLogoOverride() {
    return getEmbeddedVariable("logooverride") === "true";
}

export function getRememberMe() {
    return getEmbeddedVariable("rememberme") === "true";
}

export function getResetPassword() {

View on GitHub (pinned to c883b8d3d8)

Solutions

  1. Serve the SPA through the Authelia backend so index.html is templated with the data-* attributes
  2. If serving statically (dev), add the attributes manually to web/index.html's body tag
  3. View page source and confirm <body> carries data-duoselfenrollment etc.; purge CDN/service-worker caches if not
  4. Check the attribute name matches exactly: the lookup is `data-${variableName}` verbatim, all lowercase
  5. After upgrades, hard-refresh or bust the index.html cache

Example fix

<!-- before -->
<body>

<!-- after (dev/static hosting; Authelia injects these server-side in production) -->
<body data-duoselfenrollment="false" data-logooverride="false" data-theme="auto" data-rememberme="true" data-resetpassword="true">
Defensive patterns

Strategy: validation

Validate before calling

const name = 'duoselfenrollment';
if (!document.body.hasAttribute(`data-${name}`)) {
    // HTML not templated by Authelia: fall back to defaults or block boot with a clear message
    return fallbackDefaults[name];
}
return getEmbeddedVariable(name);

Type guard

function hasEmbeddedVariable(name: string): boolean {
    return document.body.getAttribute(`data-${name}`) !== null;
}

Try / catch

try {
    return getEmbeddedVariable('duoselfenrollment') === 'true';
} catch (err) {
    if (err instanceof Error && err.message.includes('embedded variable')) {
        return false; // safe default; log loudly because the deployment is misconfigured
    }
    throw err;
}

Prevention

When it happens

Trigger: Loading the SPA from a source that does not template index.html: the vite dev server or a static file server hosting web/ directly; a deployment that strips body attributes; a stale cached index.html from a CDN or service worker after an upgrade.

Common situations: Running the frontend standalone in development; nginx serving the built assets instead of proxying to Authelia; an over-aggressive HTML minifier or CDN rewriting the body tag; accessing the portal through a cache holding a pre-render artifact.

Related errors

AI-assisted analysis of authelia/authelia@c883b8d3d8 (2026-08-15). Data as JSON: /api/errors/77ae67f02d613bf2. Report an issue: GitHub.