[Bug]: Nextcloud 27.0.1 unicode fqdn in CSP header

⚠️ 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

After upgrading 26 to 27.0.1, Nextcloud sets unpunicoded unicode domain in CSP header.
This prevents browsers from loading all assets.

Example CSP header generated by nextcloud

Content-Security-Policy default-src 'none';base-uri 'none';manifest-src 'self';script-src 'nonce-eVJrNk93WHBSdjNDUkNvUXI3azcxdzdSZ2ZqeXpPbEFPd0JqQnNLWUtEST06a0g1M1NqeURBWitNQmdGMjRNNVluVVdROUxmQW42NE5kellKTXFudVlIZz0=';style-src 'self' 'unsafe-inline';img-src 'self' data: blob: https://cloud.täst.de;font-src 'self' data:;connect-src 'self';media-src 'self';frame-src 'self' nc: https://cloud.täst.de;frame-ancestors 'self' https://cloud.täst.de;form-action 'self' https://cloud.täst.de.de

Affected Routes:
/apps/files
/apps/photos
/apps/contacts
/apps/calendar
/apps/phonetrack
/settings

Not affected routes:
/remote.php
/ocs
/js
/apps/keeweb

Steps to reproduce

1. Updating nextcloud from 26 to 27.0.1
2. nginx/php8.2-fpm

Expected behavior

If the instance has a unicode domain, the fqdn must be punicoded in the Content-Security-Policy header.

Installation method

Community VM appliance

Nextcloud Server version

27

Operating system

Debian/Ubuntu

PHP engine version

PHP 8.2

Web server

Nginx

Database engine version

PostgreSQL

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

Upgraded to a MAJOR version (ex. 22 to 23)

Are you using the Nextcloud Server Encryption module?

Encryption is Disabled

What user-backends are you using?

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

Configuration report

{
    "system": {
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "localhost",
            "cloud.xn--tst-qla.de"
        ],
        "trusted_proxies": "***REMOVED SENSITIVE VALUE***",
        "overwritehost": "cloud.xn--tst-qla.de",
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "pgsql",
        "version": "27.0.1.2",
        "overwrite.cli.url": "https:\/\/cloud.xn--tst-qla.de",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbtableprefix": "oc_",
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "memcache.local": "\\OC\\Memcache\\Redis",
        "memcache.distributed": "\\OC\\Memcache\\Redis",
        "memcache.locking": "\\OC\\Memcache\\Redis",
        "redis": {
            "host": "***REMOVED SENSITIVE VALUE***",
            "port": "0"
        },
        "filelocking.enabled": "true",
        "enable_previews": "true",
        "enabledPreviewProviders": [
            "OC\\Preview\\PNG",
            "OC\\Preview\\JPEG",
            "OC\\Preview\\GIF",
            "OC\\Preview\\BMP",
            "OC\\Preview\\XBitmap",
            "OC\\Preview\\Movie",
            "OC\\Preview\\PDF",
            "OC\\Preview\\MP3",
            "OC\\Preview\\TXT",
            "OC\\Preview\\MarkDown",
            "OC\\Preview\\TIFF"
        ],
        "preview_max_scale_factor": "1",
        "preview_max_memory": "256",
        "auth.bruteforce.protection.enabled": "true",
        "trashbin_retention_obligation": "auto,7",
        "skeletondirectory": "",
        "defaultapp": "file",
        "activity_expire_days": "14",
        "integrity.check.disabled": "false",
        "updater.release.channel": "stable",
        "mail_smtpmode": "smtp",
        "mail_smtpsecure": "tls",
        "mail_sendmailmode": "smtp",
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "25",
        "maintenance": false,
        "theme": "",
        "loglevel": 2,
        "default_phone_region": "de",
        "check_for_working_wellknown_setup": false,
        "allow_local_remote_servers": true
    }
}

List of activated Apps

Enabled:
  - activity: 2.19.0
  - admin_audit: 1.17.0
  - calendar: 4.4.3
  - checksum: 1.2.2
  - circles: 27.0.1
  - cloud_federation_api: 1.10.0
  - comments: 1.17.0
  - contacts: 5.3.2
  - contactsinteraction: 1.8.0
  - dav: 1.27.0
  - drawio: 2.1.2
  - federatedfilesharing: 1.17.0
  - federation: 1.17.0
  - files: 1.22.0
  - files_pdfviewer: 2.8.0
  - files_rightclick: 1.6.0
  - files_sharing: 1.19.0
  - files_trashbin: 1.17.0
  - files_versions: 1.20.0
  - groupfolders: 15.0.1
  - keeweb: 0.6.13
  - logreader: 2.12.0
  - lookup_server_connector: 1.15.0
  - nextcloud_announcements: 1.16.0
  - notifications: 2.15.0
  - oauth2: 1.15.1
  - password_policy: 1.17.0
  - phonetrack: 0.7.6
  - photos: 2.3.0
  - privacy: 1.11.0
  - provisioning_api: 1.17.0
  - recommendations: 1.6.0
  - related_resources: 1.2.0
  - richdocuments: 8.1.0
  - serverinfo: 1.17.0
  - settings: 1.9.0
  - sharebymail: 1.17.0
  - support: 1.10.0
  - systemtags: 1.17.0
  - text: 3.8.0
  - theming: 2.2.0
  - twofactor_backupcodes: 1.16.0
  - updatenotification: 1.17.0
  - user_status: 1.7.0
  - viewer: 2.1.0
  - weather_status: 1.7.0
  - workflowengine: 2.9.0
Disabled:
  - bruteforcesettings: 2.7.0
  - collectives: 2.6.1 (installed 2.6.1)
  - dashboard: 7.7.0 (installed 7.1.0)
  - encryption: 2.15.0
  - files_external: 1.19.0
  - files_markdown: 2.4.1 (installed 2.4.1)
  - firstrunwizard: 2.16.0 (installed 2.10.0)
  - ransomware_protection: 1.14.0 (installed 1.14.0)
  - survey_client: 1.15.0 (installed 1.9.0)
  - suspicious_login: 5.0.0
  - twofactor_totp: 9.0.0
  - user_ldap: 1.17.0

Nextcloud Signing status

No errors have been found.

Nextcloud Logs

No related logs

Additional info

No response

No source file or test is named. Reproduce the issue with the configured punycoded hostname and trace CSP generation for /apps/files, /apps/photos, /apps/contacts, /apps/calendar, /apps/phonetrack, and /settings, comparing them with unaffected routes such as /remote.php and /ocs. Done means the Content-Security-Policy contains the punycoded hostname and affected pages load all assets.