Ensuring the security of a Laravel application is a critical part of development. Here are some ways to ensure that your Laravel application is secure:

1. Use HTTPS: Always use HTTPS for all requests and responses to and from your application. This helps to protect user data from eavesdropping and man-in-the-middle attacks.

2. Validate User Input: Always validate user input to ensure that it’s safe and conforms to expected formats. This can prevent common attacks such as SQL injection, XSS (Cross-site Scripting), and CSRF (Cross-site Request Forgery).

3. Use Strong Passwords: Require users to create strong passwords that include a mix of letters, numbers, and special characters. Encourage them to use password managers to create and store complex passwords.

4. Implement Access Control: Use access control mechanisms to ensure that users can only access the parts of the application they’re authorized to use. This includes roles, permissions, and authentication.

5. Secure Sensitive Data: Ensure that sensitive data such as passwords and API keys are stored securely using encryption and hashing.

6. Keep Your Application Up-to-date: Stay up to date with the latest security patches and updates for Laravel and its dependencies. This can help prevent common vulnerabilities and exploits.

Common security vulnerabilities in Laravel applications include:

1. SQL Injection: Attackers can inject malicious SQL code into user input, which can then be executed by the application. This can be prevented by using parameterized queries or prepared statements.

2. XSS (Cross-site Scripting): Attackers can inject malicious code into a website, which can then be executed by unsuspecting users. This can be prevented by validating user input and escaping output.

3. CSRF (Cross-site Request Forgery): Attackers can trick users into performing actions on the application without their knowledge or consent. This can be prevented by using CSRF tokens.

4. Brute-Force Attacks: Attackers can attempt to gain unauthorized access to an application by repeatedly guessing usernames and passwords. This can be prevented by using rate limiting and lockout mechanisms.

5. Session Hijacking: Attackers can steal session cookies to gain unauthorized access to an application. This can be prevented by using secure session management practices, such as rotating session IDs and using secure session storage mechanisms.

In summary, ensuring the security of a Laravel application requires a combination of good coding practices, secure data management, and robust access control mechanisms. By staying up to date with the latest security best practices and tools, you can reduce the risk of common vulnerabilities and protect your application and its users.