Authentication bypass allows attackers to access protected resources without proper credentials, often through insecure direct object references, predictable tokens, or logic flaws.
Scan for This VulnerabilityAuthentication bypass vulnerabilities let attackers skip or circumvent login requirements. This includes accessing resources by changing IDs in URLs, exploiting JWT validation issues, or finding unprotected API endpoints. These flaws can grant unauthorized access to user data or administrative functions.
Unauthorized access to user accounts
Data theft across users
Privilege escalation to admin
Complete application compromise
Never trust client-side authentication state.
// Verify auth on every request
const { data: { user } } = await supabase.auth.getUser();
if (!user) {
return res.status(401).json({ error: 'Unauthorized' });
}Use UUIDs instead of sequential IDs.
// BAD - predictable
/api/users/1
/api/users/2
// GOOD - UUIDs
/api/users/550e8400-e29b-41d4-a716-446655440000Check ownership, not just authentication.
// Check user owns the resource
const { data } = await supabase
.from('posts')
.select()
.eq('id', postId)
.eq('user_id', user.id)
.single();
if (!data) {
return res.status(403).json({ error: 'Forbidden' });
}VAS automatically scans for authentication bypass and provides detailed remediation guidance.
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