Before reporting an issue

[x] I have read and understood the above terms for submitting issues, and I understand that my issue may be closed without action if I do not follow them.

Area

core

Describe the bug

The /admin endpoint redirects to the Admin Console for convenience. However this might disclose the admin hostname when hostname-admin is configured.

Version

main

Regression

[ ] The issue is a regression

Expected behavior

Redirect to Admin Console is performed only when /admin is accessed via the Admin Hostname (which falls back to frontend when hostname-admin is not configured).

Actual behavior

Redirect always happens.

How to Reproduce?

Start Keycloak as:

kc.sh start --http-enabled=true --hostname http://127.0.0.1.nip.io:8080/ --hostname-admin http://admin.127.0.0.1.nip.io:8080/

Run:

curl http://127.0.0.1.nip.io:8080/admin -v

Observe:

Location: http://admin.127.0.0.1.nip.io:8080/admin/master/console/

Anything else?

No response