Supabase Security Directory

What this Supabase security directory is

This is the hub for Mockly’s Supabase security guides: terms, fix templates, examples, integrations, and tool workflows.

Use it when you want to go from “what is this risk?” to “how do I fix it and prove it’s fixed?” without bouncing between random docs.

How to navigate the Supabase security directory

Use this hub as a decision tree. Pick your intent first, then follow internal links to get deeper without getting lost.

• Start with the glossary to learn a concept and the “what to check” signals.
• Use templates when you need copy/paste changes plus verification steps.
• Use conversions when you need the full transformation (from unsafe → safe) with examples.
• Use examples when you want to recognize patterns and avoid repeating mistakes.
• Use integrations when you’re implementing a secure workflow (signed URLs, server-only RPC, backend-only tables).
• Use curation/comparisons/profiles when you’re choosing a workflow or tool based on tradeoffs.

Recommended starting points (high leverage)

Glossary terms to learn first

• Admin Panel Client-Only Auth → /glossary/admin-panel-client-auth-only — Admin Panel Client-Only Auth is a Supabase security risk where admin protections live in frontend checks instead of enforceable backend authorization, .
• API Cache Leaks Private Data → /glossary/api-cache-private-data-leak — API Cache Leaks Private Data is a Supabase security risk where shared caches return user-specific responses to unauthorized sessions, .
• Audit Log Table Publicly Readable → /glossary/audit-log-public-readable — Audit Log Table Publicly Readable is a Supabase security risk where diagnostic or audit tables become queryable by client roles, .
• Auth Role Claim Confusion → /glossary/auth-role-claim-confusion — Auth Role Claim Confusion is a Supabase security risk where role mapping is ambiguous and grants unintended privileges to users, .
• Billing Webhook Idempotency Gap → /glossary/billing-webhook-idempotency-gap — Billing Webhook Idempotency Gap is a Supabase security risk where billing events are processed multiple times and create inconsistent account states, .
• Broad DELETE for Authenticated Role → /glossary/broad-authenticated-delete — Broad authenticated DELETE grants allow any logged-in user to remove rows.
• Broad SELECT for Authenticated Role → /glossary/broad-authenticated-select — Broad authenticated SELECT grants let every logged-in user read sensitive tables.
• Broad UPDATE for Authenticated Role → /glossary/broad-authenticated-update — Broad authenticated UPDATE grants let every logged-in user change other people’s rows.

Templates to apply first

• Lock down a public table (backend-only access) → /templates/access-control/lock-down-public-table — A template to revoke direct client access, enable RLS, remove policies, and force all reads/writes through your backend using service_role.
• Lock down RPC: revoke EXECUTE from public roles → /templates/rpc-functions/lock-down-rpc-execute — A template to discover function signatures, revoke EXECUTE from PUBLIC/anon/authenticated, and call RPC only through backend code using service_role.
• Make a bucket private + serve files with signed URLs → /templates/storage-safety/make-bucket-private-signed-urls — A template to make Supabase Storage buckets private, prevent listing/enumeration, and deliver downloads using short-lived signed URLs from your backend.
• Remove over-permissive RLS policies (adopt deny-by-default) → /templates/access-control/remove-over-permissive-policies — A template to remove broad policies that leak data and move to a backend-only, deny-by-default posture that is easier to reason about and verify.

Integrations to implement first

• .NET API Rate Protection Supabase security integration → /integrations/dotnet-api-rate-protection-supabase-security — .NET API Rate Protection Supabase security integration helps teams apply abuse controls on endpoints that can expose or mutate sensitive data while keeping Supabase access paths verifiable across development, staging, and production.
• .NET Auth Context Validation Supabase security integration → /integrations/dotnet-auth-context-validation-supabase-security — .NET Auth Context Validation Supabase security integration helps teams validate auth context server-side before any privileged Supabase operation while keeping Supabase access paths verifiable across development, staging, and production.
• .NET Backend Boundary Supabase security integration → /integrations/dotnet-backend-boundary-supabase-security — .NET Backend Boundary Supabase security integration helps teams route all privileged table and RPC access through server-owned authorization checks while keeping Supabase access paths verifiable across development, staging, and production.
• .NET Incident-ready Logging Supabase security integration → /integrations/dotnet-incident-ready-logging-supabase-security — .NET Incident-ready Logging Supabase security integration helps teams capture high-signal security logs for fast exposure investigation while keeping Supabase access paths verifiable across development, staging, and production.
• .NET Key Secrets Hygiene Supabase security integration → /integrations/dotnet-key-secrets-hygiene-supabase-security — .NET Key Secrets Hygiene Supabase security integration helps teams keep service-role and privileged keys server-only with rotation discipline while keeping Supabase access paths verifiable across development, staging, and production.
• .NET Least Privilege Audit Supabase security integration → /integrations/dotnet-least-privilege-audit-supabase-security — .NET Least Privilege Audit Supabase security integration helps teams continuously verify grants, policies, and role boundaries stay minimal while keeping Supabase access paths verifiable across development, staging, and production.

Available sections

What these “blogs” actually give you (so you don’t waste time)

Most Supabase security content fails in one of two ways: it’s too vague to act on, or it suggests a fix without telling you how to prove it worked.

These pages are written to be operational. A good page should help you:

• Name the exact surface at risk (table, bucket, or function)
• Understand the real failure mode (what an attacker can do via direct API access)
• Run a quick check to confirm the issue is real in your environment
• Apply a fix pattern that reduces exposure (often: backend-only + tighter grants)
• Verify the fix with a repeatable test (so you can re-run it after the next migration)

If you’re reading a page and you still can’t describe “what to test next,” jump to Templates or Examples for something more concrete.

How to find the right page fast (without reading everything)

Start by picking your intent and your surface. That usually gets you to the right page in under a minute.

• If the problem is a table (scraping, cross-tenant reads, public writes) → start in /glossary then jump to /templates.
• If the problem is Storage (public buckets, listing, guessable filenames) → start in /examples then apply signed URL patterns in /integrations.
• If the problem is RPC (functions callable from clients) → start in /glossary then use /templates to revoke EXECUTE and move calls server-side.
• If you’re deciding a workflow/tool → start in /curation, sanity-check in /comparisons, then read /profiles for tradeoffs.

If you’re not sure what the surface is, begin with /glossary and use the detection sections to map the term to the surface (tables/Storage/RPC/secrets).

How to use internal links to go from learning → fixing → verifying

Internal links are there to prevent the most common failure mode: reading ten pages and shipping nothing.

• Parent links keep you oriented (back to the main index for that section).
• Sibling links expand coverage (same section, adjacent topic).
• Cross links are the important ones: they take you to implementation pages (templates/integrations) and scenario pages (examples).

A good workflow is: read one concept page → open one implementation page → run one verification step. Then follow a sibling link only if you still have an unanswered question.

Suggested journeys (pick your goal)

Goal: learn

1. Open /glossary and pick the term that matches what you saw in a scan or audit.
2. Use the detection checklist on the term page to confirm the issue is real.
3. Follow cross-links to templates and integrations that fix the specific surface (tables, Storage, RPC).

Goal: fix fast

1. Open /templates and choose the template that matches your surface.
2. Apply the implementation steps and then run the verification checklist.
3. Use /conversions if you need a broader transformation (unsafe → safe) with examples.

Goal: choose a workflow/tool

1. Open /curation for ranked options and criteria.
2. Open /comparisons for feature matrices and verdicts.
3. Open /profiles to verify facts and understand tradeoffs before adopting a tool/process.

Keeping your Supabase security posture stable (so fixes don’t regress)

Most teams don’t get breached because they never fixed anything — they get breached because a later migration or feature quietly reintroduced exposure (drift).

After you apply a fix, keep it stable with a small habit loop:

1. Re-run a direct access test (REST/RPC/Storage) that should fail from client credentials.
2. Re-scan after schema changes that touch tables, buckets, or functions.
3. Audit grants and EXECUTE privileges periodically (especially after adding new tables/functions).
4. Keep secrets server-only and treat any exposure as an incident (rotate, then verify denial with old credentials).

If you only do one thing: always verify via direct access. Attackers don’t use your UI.