Fabric Security

Security model

Permission Layers (broadest to finest)

1. Workspace roles: Admin, Member, Contributor, Viewer
2. Item-level permissions: Read, ReadData, ReadAll
3. OneLake security data access roles (GA May 2026): lake-level RBAC — folder + row + column scopes enforced across all Fabric engines (see below)
4. SQL granular permissions: GRANT/DENY/REVOKE

Key Principles

• Admin/Member/Contributor roles grant full data read and bypass RLS/CLS/DDM
• Use Viewer role + SQL GRANT for least-privilege consumer access
• Sharing an item with no extra permissions → CONNECT only (can't read tables until GRANT SELECT)
• "Read all data using SQL" (ReadData) → equivalent to db_datareader
• "Read all data using Apache Spark" (ReadAll) → OneLake file access, does NOT affect SQL permissions
• RLS/CLS enforcement is mode-dependent (changed by OneLake security GA, May 2026):
  • SQL-defined RLS/CLS (the CREATE SECURITY POLICY / column-GRANT surface below) is still enforced on the SQL endpoint only — users with Spark/OneLake access (ReadAll) bypass it. This hole is unchanged.
  • OneLake-security-defined RLS/CLS (lake-level data access roles) is enforced across all Fabric engines — Lakehouse, Spark notebooks, Direct Lake on OneLake, and SQL analytics endpoints switched to User's identity access mode are all GA. "Any security set applies to access from all engines in Fabric." SQL analytics endpoints left in delegated-identity mode do not honor OneLake security roles (they keep the old behavior). The mode is a one-time per-endpoint switch under the endpoint Security tab; newer SQL analytics endpoints default to user's-identity mode.
• Users auto-created on first GRANT/DENY — CREATE USER is not supported
• Limit warehouses + SQLEPs to ≤ 40 per workspace to avoid system token size limits

SQL Granular Permissions

Users are auto-created on first GRANT/DENY — CREATE USER is not supported (and not needed).

-- Object-level
GRANT SELECT  ON dbo.FactSales TO [analyst@contoso.com];
DENY  SELECT  ON dbo.EmployeeSalary TO [analyst@contoso.com];
GRANT EXECUTE ON dbo.sp_TopProducts TO [analyst@contoso.com];
GRANT SELECT  ON SCHEMA::reporting TO [powerbi_readers@contoso.com];

-- Column-level (CLS) — column list in GRANT or DENY
GRANT SELECT ON dbo.Customers (CustomerID, CustomerName, Region) TO [viewer@contoso.com];
DENY  SELECT ON dbo.Customers (SSN, CreditCardNumber)            TO [viewer@contoso.com];

Row-Level Security (RLS)

CREATE SCHEMA rls;
GO
CREATE FUNCTION rls.fn_securitypredicate(@SalesRep AS varchar(60))
RETURNS TABLE WITH SCHEMABINDING
AS RETURN SELECT 1 AS result
   WHERE @SalesRep = USER_NAME() OR USER_NAME() = 'manager@contoso.com';
GO
CREATE SECURITY POLICY dbo.SalesFilter
ADD FILTER PREDICATE rls.fn_securitypredicate(SalesRep) ON dbo.Sales
WITH (STATE = ON);

Test as the actual target user — owner-testing bypasses RLS.

Dynamic Data Masking (DDM) — Warehouse only

CREATE TABLE dbo.Customers (
    CustomerID int NOT NULL,
    FullName varchar(100) MASKED WITH (FUNCTION = 'partial(1,"XXXXX",1)') NULL,
    Email    varchar(100) MASKED WITH (FUNCTION = 'email()')              NULL,
    Phone    varchar(20)  MASKED WITH (FUNCTION = 'default()')            NULL,
    SSN      varchar(11)  MASKED WITH (FUNCTION = 'partial(0,"XXX-XX-",4)') NULL
);

GRANT UNMASK ON dbo.Customers TO [finance_team@contoso.com];

DDM is a viewing restriction, not encryption. Workspace Admin / Member / Contributor see unmasked data by default — DDM only protects Viewer-role users.

OneLake Security (GA May 2026)

Lake-level RBAC enforced across all Fabric engines, distinct from the SQL GRANT surface. Deny-by-default: a user in no data access role sees no data in the item.

• Data access roles: each role = a permission (Read or ReadWrite) + a scope (tables/folders/schemas) + Entra members. Only GRANT-type roles exist. Tables can carry row- and/or column-level security inside a role. Created/managed by Write+Reshare users (Admin/Member) via the item's OneLake security UX.
• Supported items: Lakehouse (Read, ReadWrite), Azure Databricks Mirrored Catalog (Read), Mirrored Databases (Read).
• ReadWrite permission (Lakehouse): lets a Viewer/Read user write to specified tables/folders (Spark notebooks, OneLake file explorer, OneLake APIs) without item create/manage rights — not through the Lakehouse UX. Roles with ReadWrite can't carry RLS/CLS.
• Virtualized (default) role memberships: new items ship a DefaultReader role whose members are virtualized — every user with the ReadAll permission is implicitly a member, so they see all data. Restrict by deleting DefaultReader, removing ReadAll, or replacing it with a custom role.
• Gotcha — remove from DefaultReader: after adding a user to a scoped data access role, remove them from DefaultReader, or they retain full access through it and the scoped role is moot.
• Engine enforcement (GA): Lakehouse, Spark notebooks, SQL analytics endpoint in user's-identity mode, and Direct Lake on OneLake all apply RLS/CLS filtering. Eventhouse (RLS only) and authorized third-party engines are still preview. For user access (unauthorized external engines) to RLS/CLS data, the query is blocked, not silently filtered.
• Admin/Member/Contributor still override: their implicit OneLake Write permission overrides any OneLake security Read role — these roles are not constrained by data access roles (consistent with the RLS/CLS/DDM bypass above).
• Role-definition changes take ~5 min to apply; user-group membership changes ~1 hr (plus per-engine cache).

Sensitivity Labels (REST-discoverable)

Item-level Purview labels became programmatically discoverable on the core item REST surface in March 2026 GA: GET /v1/workspaces/{wsId}/items and GET /v1/workspaces/{wsId}/items/{itemId} now include sensitivityLabel: { "sensitivityLabelId": "<labelGuid>" } on the Item object when a label is applied (field omitted on unlabeled items). Note the inner field is sensitivityLabelId at runtime — the MS Learn schema page calls it id, but the live API returns sensitivityLabelId (verified on 233/233 labeled items, May 2026). Any caller with the Viewer workspace role + Workspace.Read.All can read it — no admin elevation needed — making label-coverage audits possible without Fabric admin privileges. Only the GUID is returned; resolve to a human-readable name via Microsoft Graph /security/informationProtection/sensitivityLabels. Setting or removing labels still requires the existing admin APIs (/v1/admin/labels/bulkSetLabels / bulkRemoveLabels — Fabric admin role, Tenant.ReadWrite.All). See [[fabric-rest-api]] for the response shape.

Reference

• Microsoft Learn: Security in Microsoft Fabric (overview)
• Microsoft Learn: Permission model
• Microsoft Learn: OneLake security — get started
• Comprehensive MS Learn link bundle (concept / workspace+item / OneLake security / per-item auth / workspace identity & SPN / network security / sensitivity labels / troubleshooting): references/REFERENCE.md

See also

• fabric-warehouse skill — SQL GRANT/DENY surface on Warehouse
• fabric-auth skill — token audiences for each access path