What Is RBAC vs ABAC vs FGAC?
- Focus
- RBAC vs ABAC
- Risk
- High
- Stack
- Supabase RLS
- Detection
- Ubserve Runtime Simulation
RBAC vs ABAC vs FGAC is an authorization model comparison that shows how access rules are defined and enforced. The choice affects tenant isolation and product flexibility.
RBAC assigns permissions by role, ABAC evaluates policy from attributes, and FGAC enforces permissions at detailed resource scope such as rows, fields, or actions. AI-built SaaS stacks usually need all three layers working together, not a single model used in isolation.
A role-only setup can look correct in demos while still exposing sensitive records in production. This is common in generated auth code where "admin" and "member" checks exist, but object ownership, tenant boundaries, and field-level restrictions are missing.
A simple analogy: RBAC is like giving someone a job title badge, ABAC is checking additional context like time and location, and FGAC is deciding exactly which file cabinet drawer they can open. Modern SaaS security fails when teams stop at the badge.
[Component: DarkWireframeKey]
As shown in the Policy Gate diagram, the left lane should represent high-level role entitlement, and the right lane should represent fine-grained row/object authorization enforcement.
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Agentic Risk (Cursor, v0, Bolt)
Generated auth logic often stops at RBAC checks and misses object-level constraints. Ubserve 2026 findings show 21.7% of AI-built apps had role-correct but object-insecure flows.
Wrong vs. Right
WRONG: "admin|member" role check only
RIGHT: role check + tenant attribute + object ownership/FGAC policy
Copy-Paste Fix Prompt for Cursor/Claude
Refactor my authorization model using RBAC + FGAC.
1) Keep RBAC for broad action classes.
2) Add FGAC policies for tenant/object-level reads and writes.
3) Add ABAC claims where role-only logic is insufficient.
4) Produce migration steps and regression tests.
Return policy matrix + code updates.
Related resources
How Ubserve Applies This in Real Scans
Ubserve treats What Is RBAC vs ABAC vs FGAC? as a production risk, not a theory term. Our runtime simulation maps this control to attacker paths in auth, data access, and API behavior, then returns fix-ready guidance tied to your stack. OWASP-style principles are used as the baseline, but we prioritize what is actually exploitable in your live flow.
Runtime exploit simulation + behavioral authorization checks.
Clear proof path showing where trust boundaries fail.
AI-ready fix prompts and implementation-level patch guidance.
FAQs
Which model is best for multi-tenant SaaS?+
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