OWASP Top 10 Vulnerabilities 2025: What Actually Changed and What Developers Keep Getting Wrong

The 2025 List Isn't What You'd Expect

Most developers assume injection is still the #1 web security risk. It hasn't been since 2021. Broken Access Control has held the top spot for years, and the OWASP Top 10 continues to reflect that reality heading into 2025.

The surprising part? The vulnerability that causes the most real-world breaches isn't exotic. It's developers forgetting to check whether a user should actually be allowed to do what they're requesting.

The 2025 OWASP Top 10 Vulnerabilities at a Glance

A01: Broken Access Control — Still #1. IDOR flaws everywhere.
A02: Cryptographic Failures — Plaintext secrets, weak hashing, expired certs.
A03: Injection — SQL, NoSQL, OS command, LDAP. Dropped from the throne but still deadly.
A04: Insecure Design — Flaws baked into architecture, not just implementation.
A05: Security Misconfiguration — Default creds, open S3 buckets, verbose error pages.
A06: Vulnerable and Outdated Components — Your dependencies are someone else's code you didn't audit.
A07: Identification and Authentication Failures — Broken session management, weak password policies.
A08: Software and Data Integrity Failures — CI/CD pipeline attacks, unsigned updates.
A09: Security Logging and Monitoring Failures — You can't respond to what you can't see.
A10: Server-Side Request Forgery (SSRF) — Cloud metadata endpoints remain a goldmine for attackers.

The structure is largely stable from the 2021 revision, but the weight of each category shifts as OWASP aggregates new breach data and CWE mappings. Insecure Design (A04) and SSRF (A10) are the newer entries that keep climbing in real-world incident reports.

The #1 Mistake: Broken Access Control in Practice

Here's the pattern that shows up in nearly every codebase audit. A developer builds an API endpoint and checks authentication but skips authorization:

// VULNERABLE: Checks if user is logged in, but not if they own this resource
app.get('/api/invoices/:id', authenticate, async (req, res) => {
  const invoice = await Invoice.findById(req.params.id);
  res.json(invoice);
});

Any authenticated user can fetch any invoice by guessing or iterating IDs. This is an Insecure Direct Object Reference (IDOR) — the single most common access control flaw.

// FIXED: Verify the resource belongs to the requesting user
app.get('/api/invoices/:id', authenticate, async (req, res) => {
  const invoice = await Invoice.findById(req.params.id);
  if (!invoice || invoice.userId !== req.user.id) {
    return res.status(404).json({ error: 'Not found' });
  }
  res.json(invoice);
});

Return 404, not 403. A 403 confirms the resource exists — that's information leakage.

Why This Keeps Happening

Frameworks handle authentication well but leave authorization to you.
Unit tests rarely cover "User A tries to access User B's data" scenarios.
REST conventions make resource IDs predictable by design.

The Sleeper Threat: Insecure Design (A04)

This category is different from the others because you can't fix it with a code patch. Insecure design means the architecture itself has no defense against certain attacks.

Example: a password reset flow that sends a 4-digit code with no rate limiting. The implementation could be flawless — clean code, parameterized queries, proper TLS — and an attacker still brute-forces it in under 30 minutes. The design is the vulnerability.

Threat modeling before writing code is the only fix. Ask: "How would I abuse this feature if I were malicious?" during the design phase, not after deployment.

What to Actually Do About It

Skip the generic "stay updated" advice. Here are three specific actions:

Add authorization tests to your CI pipeline. For every API endpoint, write a test where User A tries to access User B's resources. Automate this. Tools like PreBreach can scan your live app for access control gaps and OWASP Top 10 issues without manual test-writing.
Audit your dependencies this week. Run npm audit, pip audit, or bundle audit right now. A06 (Vulnerable Components) is the easiest category to fix and the most neglected.
Implement centralized authorization logic. Don't scatter permission checks across individual route handlers. Use middleware or a policy engine (like CASL, Casbin, or OPA) so access rules are defined once and enforced everywhere.

The OWASP Top 10 isn't a checklist to frame on your wall. It's a prioritization guide. Start with A01, write the authorization test you've been skipping, and work down from there.

The 2025 List Isn't What You'd Expect

The 2025 OWASP Top 10 Vulnerabilities at a Glance

A01: Broken Access Control — Still #1. IDOR flaws everywhere.
A02: Cryptographic Failures — Plaintext secrets, weak hashing, expired certs.
A03: Injection — SQL, NoSQL, OS command, LDAP. Dropped from the throne but still deadly.
A04: Insecure Design — Flaws baked into architecture, not just implementation.
A05: Security Misconfiguration — Default creds, open S3 buckets, verbose error pages.
A06: Vulnerable and Outdated Components — Your dependencies are someone else's code you didn't audit.
A07: Identification and Authentication Failures — Broken session management, weak password policies.
A08: Software and Data Integrity Failures — CI/CD pipeline attacks, unsigned updates.
A09: Security Logging and Monitoring Failures — You can't respond to what you can't see.
A10: Server-Side Request Forgery (SSRF) — Cloud metadata endpoints remain a goldmine for attackers.

The #1 Mistake: Broken Access Control in Practice

Here's the pattern that shows up in nearly every codebase audit. A developer builds an API endpoint and checks authentication but skips authorization:

// VULNERABLE: Checks if user is logged in, but not if they own this resource
app.get('/api/invoices/:id', authenticate, async (req, res) => {
  const invoice = await Invoice.findById(req.params.id);
  res.json(invoice);
});

Any authenticated user can fetch any invoice by guessing or iterating IDs. This is an Insecure Direct Object Reference (IDOR) — the single most common access control flaw.

// FIXED: Verify the resource belongs to the requesting user
app.get('/api/invoices/:id', authenticate, async (req, res) => {
  const invoice = await Invoice.findById(req.params.id);
  if (!invoice || invoice.userId !== req.user.id) {
    return res.status(404).json({ error: 'Not found' });
  }
  res.json(invoice);
});

Return 404, not 403. A 403 confirms the resource exists — that's information leakage.

Why This Keeps Happening

Frameworks handle authentication well but leave authorization to you.
Unit tests rarely cover "User A tries to access User B's data" scenarios.
REST conventions make resource IDs predictable by design.

The Sleeper Threat: Insecure Design (A04)

This category is different from the others because you can't fix it with a code patch. Insecure design means the architecture itself has no defense against certain attacks.

Threat modeling before writing code is the only fix. Ask: "How would I abuse this feature if I were malicious?" during the design phase, not after deployment.

What to Actually Do About It

Skip the generic "stay updated" advice. Here are three specific actions:

Add authorization tests to your CI pipeline. For every API endpoint, write a test where User A tries to access User B's resources. Automate this. Tools like PreBreach can scan your live app for access control gaps and OWASP Top 10 issues without manual test-writing.
Audit your dependencies this week. Run npm audit, pip audit, or bundle audit right now. A06 (Vulnerable Components) is the easiest category to fix and the most neglected.
Implement centralized authorization logic. Don't scatter permission checks across individual route handlers. Use middleware or a policy engine (like CASL, Casbin, or OPA) so access rules are defined once and enforced everywhere.

The OWASP Top 10 isn't a checklist to frame on your wall. It's a prioritization guide. Start with A01, write the authorization test you've been skipping, and work down from there.