Memory exhaustion when checking permissions user doesn't have via @can() directive

[CodedTerabyte]

Description

Spatie Laravel Permission - Bug Report

Summary

Memory exhaustion (134MB limit) when checking permissions that a user doesn't have via @can() Blade directive, specifically affecting users with the "applicant" role.

Environment

• Package Version: spatie/laravel-permission v6.21.0
• Laravel Version: 10.x
• PHP Version: 8.1+
• Database: MySQL/PostgreSQL

Bug Description

When a user (specifically with role "applicant") accesses a page with multiple @can() Blade directives checking permissions they DON'T have, the system runs out of memory:

PHP Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 12288 bytes)
in /vendor/spatie/laravel-permission/src/Guard.php on line 69

Hypothesis

The Guard class appears to have an infinite loop or recursive query when:

1. User has a role with limited permissions (e.g., 9 permissions)
2. Multiple @can() checks are made for permissions they DON'T have
3. The "permission denied" code path triggers excessive memory allocation

Possible causes:

• Circular relationship loading
• N+1 query problem in permission resolution
• Missing cache/memoization for negative permission checks
• Recursive getAllPermissions() calls

Workaround

We worked around this by bypassing Spatie's Guard for affected users and querying permissions directly:

// Direct DB query instead of Spatie's Guard
$hasPermission = DB::table('permissions as p')
    ->join('role_has_permissions as rhp', 'p.id', '=', 'rhp.permission_id')
    ->join('model_has_roles as mhr', 'rhp.role_id', '=', 'mhr.role_id')
    ->where('mhr.model_type', 'App\\Models\\User')
    ->where('mhr.model_id', $userId)
    ->where('p.name', $permissionName)
    ->exists();

This works perfectly with no memory issues.

Expected Behavior

@can() checks should return false quickly for permissions user doesn't have, without memory exhaustion.

Actual Behavior

Memory exhaustion when checking multiple permissions user doesn't have.

Additional Context

Database structure:

• 55 total permissions in system
• Applicant role has 9 permissions
• Admin role has 55 permissions
• Officer role has 23 permissions

Permission IDs:

• Min ID: 109
• Max ID: 163
• Applicant permission IDs: 109, 110, 111, 112, 118, 126, 127, 131, 157

Questions for Maintainers

1. Is there known caching mechanism that could cause this?
2. Should we investigate the Gate/Guard resolution for negative checks?
3. Would eager loading permissions prevent this issue?
4. Is this related to permission ID ranges (starting at 109 vs 1)?

Willing to Contribute

I'm willing to:

• Create a failing test case
• Debug the Guard.php code to find exact issue
• Submit a PR with a fix
• Test the fix thoroughly

Please advise on next steps!

Steps To Reproduce

Reproduction Steps

1. Setup

# Create a role with limited permissions
php artisan tinker
$applicant = Role::create(['name' => 'applicant']);
$applicant->givePermissionTo(['view applications', 'create applications']);

2. Create a user with this role

$user = User::create([
    'email' => 'applicant@test.com',
    'password' => bcrypt('password'),
    'role' => 'applicant'
]);
$user->assignRole('applicant');

3. Create a Blade view with multiple permission checks

{{-- resources/views/layouts/app.blade.php --}}
<nav>
    @can('view applications')
        <a href="/applications">Applications</a>
    @endcan

    @can('review applications') {{-- User DOESN'T have this --}}
        <a href="/reviews">Reviews</a>
    @endcan

    @can('view audit logs') {{-- User DOESN'T have this --}}
        <a href="/audit">Audit Logs</a>
    @endcan

    @can('view reports') {{-- User DOESN'T have this --}}
        <a href="/reports">Reports</a>
    @endcan

    {{-- Add 10+ more @can() checks for permissions user doesn't have --}}
</nav>

4. Login as applicant and view the page

The page will hang and eventually crash with memory exhaustion.

Key Findings

1. Works fine in Tinker:

$user = User::find(9);
$user->can('review applications'); // Returns false - no memory issue

2. Fails in web request with Blade: When the layout renders with multiple @can() directives

3. Only affects certain users:

   • ✅ Admin users with MANY permissions: Works fine
   • ✅ Officer users with MODERATE permissions: Works fine
   • ❌ Applicant users with FEW permissions: Memory exhaustion

4. Triggers on denied permissions: The bug occurs when checking permissions the user doesn't have

Stack Trace

Allowed memory size of 134217728 bytes exhausted (tried to allocate 552960 bytes)
at vendor/laravel/framework/src/Illuminate/Database/Eloquent/Collection.php:554

Context shows the error originates from:
vendor/spatie/laravel-permission/src/Guard.php:69

### Example Application

_No response_

### Version of spatie/laravel-permission package:

spatie/laravel-permission v6.21.0

### Version of laravel/framework package:

10.x

### PHP version:

8.1+

### Database engine and version:

MySQL/PostgreSQL

### OS: Windows/Mac/Linux version:

Mac

[drbyte]

Thanks for the detailed report.

I'm surprised that the collect()->map() call on line 69 would cause a memory leak. How many auth.guard array entries do you have (both in your main config, and imported by other packages)?
It's also only called if the model you're checking permissions for doesn't have a guard_name property (or guardName() method) on it (not that you need it, but that is commonly used if you have only 1 guard to check for, for that model or perhaps for your entire app).

Yes, a failing test is worthwhile. Also profiling to determine why Blade is behaving differently than Tinker.

I'd like to see a barebones demo application created as minimalistic as possible just to recreate this problem, as that's the best way to help narrow down root causes, and rule-out other packages and other app content.

Is there known caching mechanism that could cause this?

The caching in this package shouldn't have anything to do with negative checks.
Caching is two-fold: a memoized array of found records, fed from an Eloquent query wrapped by usual Laravel caching activity to minimize repeat queries.

Should we investigate the Gate/Guard resolution for negative checks?

There might be something about Laravel's gate that's doing something with negative checks.
This package does nothing with negative checks other than return false.

Would eager loading permissions prevent this issue?

Doubtful.

Is this related to permission ID ranges (starting at 109 vs 1)?

No. Apps with thousands of permissions and/or roles aren't reporting these symptoms.