OWASP Top 10 2025: The Complete Guide to the Most Critical Web Vulnerabilities

What Is the OWASP Top 10?

The OWASP Top 10 is a document maintained by OWASP (Open Worldwide Application Security Project) that brings together the most critical vulnerabilities found in web applications.

The project is based on real data collected from thousands of applications assessed by companies, consultancies, and offensive security professionals around the world.

The goal of the Top 10 is not to list every existing vulnerability, but to highlight the most relevant, exploitable, and frequently encountered risks in real-world environments.

What Changed in the OWASP Top 10 2025?

The 2025 edition brought important changes compared to the OWASP Top 10 2021.

The focus shifted much more toward:

• Modern APIs
• Cloud Security
• Supply Chain
• CI/CD pipelines
• Insecure configurations
• Application architecture
• Resilience and error handling

Key changes in the 2025 edition

• Security Misconfiguration moved up to position #2
• Software Supply Chain Failures replaced "Vulnerable and Outdated Components"
• SSRF was folded into Broken Access Control
• Mishandling of Exceptional Conditions entered as a new category
• Greater focus on root causes rather than just symptoms

OWASP Top 10 2025 — Official List

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A01:2025 – Broken Access Control

Broken Access Control remains the most critical vulnerability in the OWASP Top 10 2025.

This problem occurs when the application fails to properly validate whether a user actually has permission to access a given resource.

Today, most cases occur in REST APIs used by SPAs, mobile apps, and microservices-based architectures.

Common problems found in pentests

• IDORs in APIs
• Horizontal privilege escalation
• Vertical privilege escalation
• SSRF
• Cross-tenant exposure
• Authorization bypass

Vulnerable Example

// Vulnerable

app.get('/api/orders/:id', authenticate, async (req, res) => {

    const order = await db.orders.findUnique({
        where: {
            id: req.params.id
        }
    });

    res.json(order);

});
    

Problem

The backend only validates authentication, but never checks whether the order belongs to the authenticated user.

Fix

// Secure

app.get('/api/orders/:id', authenticate, async (req, res) => {

    const order = await db.orders.findFirst({
        where: {
            id: req.params.id,
            ownerId: req.user.id
        }
    });

    if (!order) {
        return res.status(404).json({
            error: 'Not found'
        });
    }

    res.json(order);

});
    

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A02:2025 – Security Misconfiguration

Security Misconfiguration grew significantly due to the increasing complexity of cloud environments, containers, Kubernetes, and modern infrastructure.

Common examples

• Public buckets
• Debug mode enabled in production
• Exposed Kubernetes
• Insecure CORS
• Excessive permissions
• Publicly accessible admin panels
• Exposed secrets

Dangerous example

// Vulnerable

app.use(cors({
    origin: '*',
    credentials: true
}));
    

Insecure configurations remain one of the most exploited flaws in modern cloud environments.

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A03:2025 – Software Supply Chain Failures

This category replaces "Vulnerable and Outdated Components" and broadens the focus to the entire software ecosystem.

Today the risk isn't only in vulnerable libraries, but also in:

• Compromised CI/CD pipelines
• Malicious packages
• Insecure dependencies
• Compromised build systems
• Supply chain attacks

Important tools

• Dependabot
• Snyk
• Trivy
• npm audit
• SBOM

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A04:2025 – Cryptographic Failures

Cryptographic failures continue to cause sensitive data leaks, account compromise, and exposed secrets.

Common problems

• Passwords without proper hashing
• Insecure JWTs
• Hardcoded secrets
• Incorrect use of TLS
• Weak algorithms

// Vulnerable

const JWT_SECRET = "123456";
    

Best practices

• bcrypt or Argon2
• Secrets Manager
• Key rotation
• Properly configured TLS

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A05:2025 – Injection

Injection remains extremely relevant, especially in legacy applications and dynamic queries.

Common types

• SQL Injection
• NoSQL Injection
• Command Injection
• XSS

// Vulnerable

const query = `
SELECT * FROM users
WHERE email = '${email}'
`;

await db.raw(query);
    

Mitigation

• Prepared Statements
• Input validation
• Properly configured ORMs
• Least privilege

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A06:2025 – Insecure Design

Many modern vulnerabilities stem from architectural flaws, not just implementation errors.

Common examples

• No rate limiting
• Insecure password recovery flows
• Excessive trust in the frontend
• No segregation between tenants

Security must be considered from the application's design stage.

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A07:2025 – Authentication Failures

Authentication Failures remain relevant, especially in modern applications built on JWT and OAuth.

Common problems

• Insecure JWTs
• No MFA
• Session fixation
• Weak passwords
• Exposed refresh tokens

// Vulnerable

jwt.sign(payload, secret, {
    expiresIn: '365d'
});
    

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A08:2025 – Software or Data Integrity Failures

This category covers failures in validating the integrity of software, code, and data.

Examples

• Unverified updates
• Insecure deserialization
• Insecure pipelines
• Unverified signatures

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A09:2025 – Security Logging & Alerting Failures

Logs without effective alerting have little practical value.

Many companies only discover incidents weeks or months later.

Best practices

• Centralized logging
• SIEM
• Automated alerts
• Continuous monitoring

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A10:2025 – Mishandling of Exceptional Conditions

This new category focuses on improper error handling, logic flaws, and unsafe behavior in exceptional situations.

Common examples

• Fail open
• Overly verbose error messages
• Null pointer issues
• Improper error handling
• Bypass caused by unexpected failures

// Vulnerable

if (!user) {
    return next();
}
    

In many cases, unexpected errors end up allowing critical security flows to be bypassed.

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Tools Used in Modern Pentests

• Burp Suite Professional
• OWASP ZAP
• Caido
• ffuf
• nuclei
• httpx
• katana
• Semgrep
• Trivy
• TruffleHog

How Companies Can Reduce Risk

• Recurring pentests
• Threat Modeling
• Secure Code Review
• DevSecOps
• Continuous training
• Vulnerability management
• Automated security pipeline

Basic Security Checklist

Conclusion

The OWASP Top 10 2025 shows how modern risks are increasingly tied to APIs, cloud, supply chain, and application architecture.

Today, many serious incidents happen not because of extremely sophisticated exploits, but because of simple authorization flaws, insecure configurations, and architectural problems.

Modern security demands continuous validation, manual review, and a deep understanding of how the application behaves.

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