SSO with Microsoft Entra ID fails when UPN differs from email (login loops back to start)

[shuysmans]

Prerequisites

• I have searched the existing Closed AND Open Issues AND Discussions
• I have searched and read the documentation

Vaultwarden Support String

Your environment (Generated via diagnostics page)

• Vaultwarden version: v1.35.7
• Web-vault version: v2026.2.0
• OS/Arch: linux/x86_64
• Running within a container: true (Base: Debian)
• Database type: SQLite
• Database version: 3.51.1
• Uses config.json: true
• Uses a reverse proxy: true
• IP Header check: true (X-Real-IP)
• Internet access: true
• Internet access via a proxy: false
• DNS Check: true
• Browser/Server Time Check: false
• Server/NTP Time Check: true
• Domain Configuration Check: true
• HTTPS Check: true
• Websocket Check: true
• HTTP Response Checks: true

Config & Details (Generated via diagnostics page)

Show Config & Details

Environment settings which are overridden: DOMAIN, SIGNUPS_ALLOWED, ADMIN_TOKEN

Config:

{
  "_duo_akey": null,
  "_enable_duo": false,
  "_enable_email_2fa": false,
  "_enable_smtp": true,
  "_enable_yubico": false,
  "_icon_service_csp": "",
  "_icon_service_url": "",
  "_ip_header_enabled": true,
  "_max_note_size": 10000,
  "_smtp_img_src": "***:",
  "admin_ratelimit_max_burst": 3,
  "admin_ratelimit_seconds": 300,
  "admin_session_lifetime": 20,
  "admin_token": "***",
  "allowed_connect_src": "",
  "allowed_iframe_ancestors": "",
  "attachments_folder": "data/attachments",
  "auth_request_purge_schedule": "30 * * * * *",
  "authenticator_disable_time_drift": false,
  "data_folder": "data",
  "database_conn_init": "",
  "database_idle_timeout": 600,
  "database_max_conns": 10,
  "database_min_conns": 2,
  "database_timeout": 30,
  "database_url": "***************",
  "db_connection_retries": 15,
  "disable_2fa_remember": true,
  "disable_admin_token": false,
  "disable_icon_download": false,
  "dns_prefer_ipv6": false,
  "domain": "*****://************",
  "domain_origin": "*****://************",
  "domain_path": "",
  "domain_set": true,
  "duo_context_purge_schedule": "30 * * * * *",
  "duo_host": null,
  "duo_ikey": null,
  "duo_skey": null,
  "duo_use_iframe": false,
  "email_2fa_auto_fallback": false,
  "email_2fa_enforce_on_verified_invite": false,
  "email_attempts_limit": 3,
  "email_change_allowed": true,
  "email_expiration_time": 600,
  "email_token_size": 6,
  "emergency_access_allowed": true,
  "emergency_notification_reminder_schedule": "0 3 * * * *",
  "emergency_request_timeout_schedule": "0 7 * * * *",
  "enable_db_wal": true,
  "enable_websocket": true,
  "enforce_single_org_with_reset_pw_policy": false,
  "event_cleanup_schedule": "0 10 0 * * *",
  "events_days_retain": null,
  "experimental_client_feature_flags": "",
  "extended_logging": true,
  "helo_name": null,
  "hibp_api_key": null,
  "http_request_block_non_global_ips": true,
  "http_request_block_regex": null,
  "icon_blacklist_non_global_ips": true,
  "icon_blacklist_regex": null,
  "icon_cache_folder": "data/icon_cache",
  "icon_cache_negttl": 259200,
  "icon_cache_ttl": 2592000,
  "icon_download_timeout": 10,
  "icon_redirect_code": 302,
  "icon_service": "internal",
  "incomplete_2fa_schedule": "30 * * * * *",
  "incomplete_2fa_time_limit": 3,
  "increase_note_size_limit": false,
  "invitation_expiration_hours": 120,
  "invitation_org_name": "***************",
  "invitations_allowed": true,
  "ip_header": "X-Real-IP",
  "job_poll_interval_ms": 30000,
  "log_file": null,
  "log_level": "info",
  "log_timestamp_format": "%Y-%m-%d %H:%M:%S.%3f",
  "login_ratelimit_max_burst": 10,
  "login_ratelimit_seconds": 60,
  "org_attachment_limit": null,
  "org_creation_users": "",
  "org_events_enabled": false,
  "org_groups_enabled": false,
  "password_hints_allowed": true,
  "password_iterations": 600000,
  "purge_incomplete_sso_auth": "0 20 0 * * *",
  "push_enabled": false,
  "push_identity_uri": "https://identity.bitwarden.com",
  "push_installation_id": "***",
  "push_installation_key": "***",
  "push_relay_uri": "https://push.bitwarden.com",
  "reload_templates": false,
  "require_device_email": false,
  "rsa_key_filename": "data/rsa_key",
  "send_purge_schedule": "0 5 * * * *",
  "sendmail_command": null,
  "sends_allowed": true,
  "sends_folder": "data/sends",
  "show_password_hint": false,
  "signups_allowed": true,
  "signups_domains_whitelist": "",
  "signups_verify": true,
  "signups_verify_resend_limit": 6,
  "signups_verify_resend_time": 3600,
  "smtp_accept_invalid_certs": true,
  "smtp_accept_invalid_hostnames": true,
  "smtp_auth_mechanism": null,
  "smtp_debug": false,
  "smtp_embed_images": true,
  "smtp_explicit_tls": null,
  "smtp_from": "*****************",
  "smtp_from_name": "**********************************",
  "smtp_host": "************",
  "smtp_password": "***",
  "smtp_port": 587,
  "smtp_security": "starttls",
  "smtp_ssl": null,
  "smtp_timeout": 15,
  "smtp_username": "*****************",
  "sso_allow_unknown_email_verification": true,
  "sso_audience_trusted": null,
  "sso_auth_only_not_session": false,
  "sso_authority": "*****://*******************************************************************",
  "sso_authorize_extra_params": "",
  "sso_callback_path": "*****://*****************************************",
  "sso_client_cache_expiration": 0,
  "sso_client_id": "************************************",
  "sso_client_secret": "***",
  "sso_debug_tokens": false,
  "sso_enabled": true,
  "sso_master_password_policy": null,
  "sso_only": false,
  "sso_pkce": true,
  "sso_scopes": "openid profile email",
  "sso_signups_match_email": false,
  "templates_folder": "data/templates",
  "tmp_folder": "data/tmp",
  "trash_auto_delete_days": null,
  "trash_purge_schedule": "0 5 0 * * *",
  "use_sendmail": false,
  "use_syslog": false,
  "user_attachment_limit": null,
  "user_send_limit": null,
  "web_vault_enabled": true,
  "web_vault_folder": "web-vault/",
  "yubico_client_id": null,
  "yubico_secret_key": null,
  "yubico_server": null
}

Vaultwarden Build Version

1.35.7

Deployment method

Official Container Image

Custom deployment method

No response

Reverse Proxy

/

Host/Server Operating System

Linux

Operating System Version

Rocky Linux v10.1

Clients

Web Vault

Client Version

No response

Steps To Reproduce

1. Go to 'url'
2. FIll in username
3. Click on SSO
4. Login Entra
5. Login Succesfull
6. Goes back to loginpage

Expected Result

Login succeeding giving access to the the vault

Actual Result

Entra ID login succeeds
OIDC token exchange succeeds
User is created and visible in /admin
Login audit / mail notifications are sent
After redirect to Vaultwarden, the UI returns to the start/login screen
No Vaultwarden error is shown in the UI

Logs

Screenshots or Videos

No response

Additional Context

In our tenant, UPN and primary email address are different:

preferred_username / UPN: user@tenant.onmicrosoft.com
Email (mail attribute): firstname.lastname@organisation.tld

Vaultwarden appears to only associate SSO users based on the email claim, while Entra ID uses UPN (preferred_username) as the primary identifier.
When UPN ≠ email:

SSO authentication succeeds
User creation succeeds
Session association fails
User is redirected back to the login screen

There is no configuration option in Vaultwarden to:

Use UPN as identifier
Map preferred_username to email
Select a different claim for user binding