Kratos session AAL too low

error: session_aal2_required
error_description: This action requires a higher authenticator assurance level

Some operations (changing password, disenrolling MFA, sensitive settings changes) require the session's authenticator_assurance_level to be at least aal2. The user's current session is aal1.

How AAL is computed

A session's AAL reflects the credentials actually used to establish it:

Password alone → AAL1
Password + TOTP → AAL2
Password + WebAuthn → AAL2
Social IdP login alone → AAL1

See Identity, Sessions, AAL, refresh for the full table.

When this error fires

Changing password in settings.
Disenrolling MFA (removing TOTP / WebAuthn).
Unlinking the last credential.
Administrative operations on the user's own identity from Athena (when Athena AAL2 is configured).

User-facing fix

The user needs to step up to AAL2 by completing their second factor:

GET /self-service/login/browser?aal=aal2&refresh=true

Hera renders only the AAL2 methods (TOTP code entry, WebAuthn challenge). After successful submission, the existing session is updated to AAL2; the user can retry the original operation.

App-facing fix

If your app initiates a sensitive settings flow, expect that Kratos may reject and tell you to step up. Catch the error and redirect:

try {
  await updateSettings(...);
} catch (e) {
  if (e.error_id === 'session_aal2_required') {
    window.location.href = `/self-service/login/browser?aal=aal2&refresh=true&return_to=${returnTo}`;
    return;
  }
  throw e;
}

The user steps up; Kratos redirects back; your code retries.

When AAL2 isn't enrolled

If the user has no MFA enrolled, they can't step up. Kratos's flow gracefully handles this, it returns the user to a settings flow where they can enroll TOTP or WebAuthn first.

When AAL2 isn't required but the error fires

Check kratos.yml:

selfservice:
  flows:
    settings:
      required_aal: aal1   # change to aal1 if you want password-only for settings

The default in Olympus is aal2 for security-sensitive flows. Lowering to aal1 weakens the security model.