Overview
CVE-2020-24941 describes a flaw in Laravel versions prior to 6.18.35 and 7.x prior to 7.24.0 where the framework mishandles the $guarded property in requests that include JSON column nesting expressions. This can allow an attacker to bypass object-level authorization through mass assignment of protected attributes when the request payload contains nested JSON that maps to model attributes. The vulnerability corresponds to CWE-863 (Incorrect Authorization) and can lead to unauthorized updates to sensitive fields such as roles or admin flags in data models. The real-world impact is elevated risk for privilege escalation or data tampering in API endpoints that rely on mass assignment and complex JSON inputs. The issue was formally documented and patched in the referenced CVEs, guiding developers toward version upgrades and stricter input handling.
Affected Versions
Laravel 6.x up to 6.18.34; Laravel 7.x up to 7.23.x (CVE-2020-24941)
Code Fix Example
Laravel API Security Remediation
// Vulnerable pattern (mass-assignment with unfiltered input)
class User extends Model {
protected $guarded = ['id'];
}
public function updateVulnerable(Request $request, User $user) {
// Accepts all input, including nested JSON payloads
$input = $request->all();
$user->update($input);
}
// Fixed pattern (explicit whitelisting and validated input)
class UserSafe extends Model {
protected $fillable = ['name', 'email', 'password'];
}
public function updateFixed(Request $request, UserSafe $user) {
// Validate and only mass-assign whitelisted fields
$validated = $request->validate([
'name' => 'sometimes|string|max:255',
'email' => 'sometimes|email|max:255',
'password' => 'sometimes|string|min:8',
]);
$input =
Illuminate\Support\Arr::only($validated, ['name', 'email', 'password']);
$user->update($input);
}