Broken Access Control — 2026’s #1 Bug

If I had to bet on ONE bug class to focus on in 2026, it's this one. Broken Access Control. Bugcrowd reported critical broken access control bugs rose 36% recently — it's exploding. And the best part? It's mostly about LOGIC, not deep technical skill. Perfect for hunters at any level.

What Is Access Control?

Access control is just the rules about WHO can do WHAT. A normal user can edit their own profile. An admin can delete users. You shouldn't be able to do admin things, and you shouldn't touch other people's stuff.

Broken access control = those rules aren't actually enforced. The app TRUSTS that you'll stay in your lane… and doesn't check when you don't. 😬

It's A Whole Family Of Bugs

Broken access control is an umbrella. It includes:

• IDOR — accessing other users' data by changing IDs (we covered this!)
• Privilege escalation — a normal user doing admin actions
• Forced browsing — visiting /admin directly even though there's no link to it
• Function-level issues — calling an admin-only API as a regular user

My Favorite Test: Just Try The Admin Stuff

Seriously, this works shockingly often:

1. Log in as a normal user
2. Find out what an admin URL looks like (guess it, or find it in JavaScript files)
3. Just… go to it. /admin, /admin/users, /api/admin/delete
4. Does it work? Or does it actually block you?

You'd be amazed how many apps HIDE the admin button from normal users but forget to actually BLOCK the page. Hiding isn't securing. 😏

The Method Swap Trick

Another goodie: sometimes a GET request is blocked but the same action via POST, PUT, or DELETE isn't checked. Or the web UI blocks you but the raw API call doesn't. Always test the action directly, not just through the nice interface.

How To Hunt It Systematically

1. Make two accounts (low-privilege and another user)
2. Map out every action: who SHOULD be able to do what
3. Now try to break each rule — do admin actions as a normal user, access User B's stuff as User A
4. Try hitting endpoints directly, swapping HTTP methods, removing/changing role parameters
5. Anywhere the app trusts you instead of checking you → bug ✅

Why It Pays

Because the impact is direct and serious — reading private data, modifying other accounts, doing admin-only actions. And because it's logic-based, automated scanners are TERRIBLE at finding it. It needs a human who understands what SHOULD be allowed. That human can be you.

My Honest Tip

Think like the developer who got lazy. "I hid the button, surely that's enough." "I check permission on the main endpoint, surely nobody finds the backup one." Every lazy assumption is a bug. Find the assumption, break it.

Next post: business logic flaws — the bugs that no scanner on earth can find.

Keep breaking rules (ethically)! 🚪