[Bug]: OpenMetrics endpoint do not have to be a trusted_domain

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

Metrics Endpoint should not be evaluted to be in trusted_domains (metrics are scraped internal and the nextcloud could have changing ip address -> changing trusted_domains).

Steps to reproduce

1. setup nextcloud (behind-nginx)
2. setup openmetrics_allowed_clients
3. query /metrics

respone: HTTP/1.1 400 Bad Request

Expected behavior

response metrics

Nextcloud Server version

33

Operating system

None

PHP engine version

None

Web server

None

Database engine version

None

Is this bug present after an update or on a fresh install?

None

Are you using the Nextcloud Server Encryption module?

None

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

List of activated Apps

Nextcloud Signing status

Nextcloud Logs

{"reqId":"ZZw8YpYRIhxl2Frsp2xR","level":1,"time":"2026-02-27T15:13:25+00:00","remoteAddr":"10.42.0.188","user":"--","app":"core","method":"GET","url":"/metrics","scriptName":"/index.php","message":"Trusted domain error. \"10.42.0.188\" tried to access using \"10.42.0.150\" as host.","userAgent":"Wget","version":"33.0.0.16","data":{"app":"core"}}

Additional info

Config contains:

  ["openmetrics_allowed_clients"]=>
  array(1) {
    [0]=>
    string(12) "10.42.0.0/15"
  }

    <?php
    $CONFIG = array (
      'allow_local_remote_servers' => true,
      'trusted_proxies' => array(
        0 => '127.0.0.1',
        1 => '10.0.0.0/8',
      ),
      'forwarded_for_headers' => array('HTTP_X_FORWARDED_FOR'),
    );

Start by tracing the Nextcloud /metrics request and the openmetrics_allowed_clients check, then inspect where trusted_domains validation rejects the request. Reproduce the reported setup with a client in 10.42.0.0/15 and verify that the endpoint returns metrics without requiring the client or host to be in trusted_domains.