Web Security: OWASP Top 10 Explained

What Is OWASP and Why Its Top 10 Is the Web Security Standard

The Open Worldwide Application Security Project (OWASP) is a nonprofit organization dedicated to improving software security. Its Top 10 list is the reference standard for the most critical web vulnerabilities.

The 10 Most Critical Web Vulnerabilities According to OWASP 2026

1. Broken Access Control: The Most Common Vulnerability

The most common vulnerability. It occurs when users can access resources or functions for which they don’t have permission.

Example: a user changes /api/users/123 to /api/users/124 and accesses another user’s data.

Prevention: implement access controls on the server, never trust the client.

2. Cryptographic Failures: Sensitive Data Exposed

Sensitive data exposed due to weak or nonexistent encryption.

Prevention: always use HTTPS, encrypt data at rest, use modern algorithms (AES-256, bcrypt).

3. SQL Injection and XSS: How to Prevent Malicious Code

Malicious code inserted through user input data.

-- Vulnerable
SELECT * FROM users WHERE id = '${userInput}';

-- Secure (parameterized query)
SELECT * FROM users WHERE id = $1;

4. Insecure Design: Architectural Flaws That Can’t Be Patched

Architectural flaws that cannot be solved with good implementation.

Prevention: threat modeling from the design phase, principle of least privilege.

5. Security Misconfiguration: Headers and Ports

Insecure default configurations, open ports, missing headers.

Essential headers:

Content-Security-Policy: default-src 'self'
X-Content-Type-Options: nosniff
X-Frame-Options: DENY
Strict-Transport-Security: max-age=31536000

6. Vulnerable Dependencies: npm audit and Dependabot

Dependencies with known vulnerabilities.

Prevention: npm audit, regular updates, tools like Dependabot.

7. Insecure Authentication: Weak Passwords and Lack of MFA

Weak passwords, lack of MFA, incorrect session management.

8. Software Integrity: Compromised CI/CD Pipelines

Updates without verification, compromised CI/CD pipelines.

9. Logging and Monitoring: Detecting Breaches in Time

Failing to detect breaches in time due to lack of logging.

10. SSRF: When the Server Makes Requests for the Attacker

The server makes requests to URLs controlled by the attacker.

How to Protect Your Web Application: OWASP Security Checklist

Security is not a feature – it’s a requirement. Familiarizing yourself with the OWASP Top 10 is the first step toward building secure web applications.