Web application security has changed quite a bit since the early days of the OWASP Top 10. The list itself has changed too.
For 2026, there is an easy detail to clear up: the latest official OWASP Top 10 is the 2025 edition. It is the current reference for the most serious web application security risks, with several categories renamed or reshaped from the 2021 version.
The new list puts greater attention on supply chains, configuration, software integrity and failures that happen when applications encounter conditions outside the expected path.
1. Broken Access Control
Access control determines what an authenticated user is allowed to see or do.
A weakness here can be as simple as an application accepting a user-supplied account ID without checking whether that account actually belongs to the logged-in user. The result can be unauthorised data access, modification or deletion.
OWASP keeps Broken Access Control at A01, and the 2025 category also incorporates Server-Side Request Forgery (SSRF).
Useful controls include:
- Server-side permission checks
- Least-privilege access
- Denying access by default
- Testing object-level authorisation
- Reviewing administrative functions separately
2. Security Misconfiguration
Applications rarely fail only because of bad code. Configuration can cause trouble too.
Debug settings left enabled in production, unnecessary services, permissive cross-origin policies, exposed administrative interfaces and poorly configured cloud resources can all create openings.
OWASP moved Security Misconfiguration to A02 in 2025, reflecting its increased presence in application security data.
Configuration should therefore be treated as part of the security review. Secure defaults, hardened production environments and automated configuration checks can remove many avoidable weaknesses.
3. Software Supply Chain Failures
Modern applications depend on far more than their own source code.
Third-party packages, container images, plugins, build tools, repositories and CI/CD systems all form part of the delivery chain. A compromise somewhere along that route can eventually reach production.
This is one of the major changes in the current OWASP Top 10. Software Supply Chain Failures expands the old vulnerable-components category to cover a wider range of weaknesses across dependencies, build systems and distribution processes.
Dependency inventories, trusted repositories, signed packages and protected build pipelines are practical starting points.
4. Cryptographic Failures
Encryption can fail in several ways.
Sensitive information may be transmitted without adequate protection. Weak algorithms may be used. Keys may be exposed or stored carelessly. Random values used for security functions may also be predictable.
OWASP places these issues under A04:2025 Cryptographic Failures.
HTTPS should be standard for web applications, but transport encryption is only one piece. Password storage, key management, certificates, secrets and encryption at rest all deserve separate checks.
5. Injection
Injection remains a familiar problem because applications constantly process external input.
SQL injection is the classic example, but the category extends beyond databases. Command injection, LDAP injection and other forms can occur when untrusted data reaches an interpreter without proper handling.
Parameterised queries, safe APIs, input validation and context-aware output encoding reduce the risk. Security testing should also cover less obvious input paths, including headers, JSON fields, cookies and API parameters.
6. Insecure Design
Some security problems cannot be fixed by changing a single line of code.
An application may have a flawed business process from the beginning. A password-reset workflow might permit abuse. A financial operation might lack transaction limits. A file-upload feature might trust a dangerous assumption.
That is the territory covered by A06:2025 Insecure Design. OWASP recommends stronger use of threat modelling, secure design patterns and security requirements before coding starts.
The earlier a design flaw is found, the less painful the correction tends to be.
7. Authentication Failures
Authentication confirms that a user is who the application says they are.
Weak passwords, hard-coded credentials, session fixation, poor certificate validation and flawed authentication logic can undermine that process. OWASP renamed this category Authentication Failures in 2025 while retaining its A07 position.
Strong password policies, secure session handling, multi-factor authentication and established authentication frameworks can reduce exposure.
8. Software or Data Integrity Failures
Applications often trust software and data without checking whether either has been altered.
That assumption can become dangerous when an application loads plugins, modules, packages or other components from sources that have not been properly verified. CI/CD pipelines are another concern, particularly when build artifacts are not protected or checked for integrity.
Trusted sources, integrity checks and controlled deployment processes help preserve that chain of trust.
9. Security Logging and Alerting Failures
A breach that cannot be detected can continue for far longer than necessary.
Authentication failures, privilege changes, suspicious transactions and other security events should generate useful records. Those records also need protection and monitoring.
OWASP specifically added alerting to the category name because collecting logs without acting on meaningful events has limited security value.
Centralised logging, sensible alerts, protected log storage and defined incident-response procedures make the difference.
10. Mishandling of Exceptional Conditions
Applications do not always behave as expected.
Services fail. Requests arrive incomplete. Permissions change halfway through an operation. Dependencies become unavailable. An application that responds to these situations by “failing open” can accidentally bypass security controls.
Mishandling of Exceptional Conditions is a new category in the 2025 OWASP Top 10. It covers improper error handling, logical mistakes and failures that occur when abnormal conditions are handled insecurely.
Error handling should therefore be tested as part of security testing, not treated purely as a reliability concern.
Conclusion
The OWASP Top 10 remains a useful starting point for web application security, but it should not become a checklist that gets ticked once a year.
The 2025 edition, which is the current OWASP Top 10 reference for 2026, puts clear emphasis on access control, configuration, software supply chains, cryptography, authentication, integrity and secure handling of unexpected conditions.
For development teams, the practical lesson is straightforward: security needs to exist in architecture, source code, dependencies, deployment pipelines and production monitoring. Fixing vulnerabilities after release is far more expensive than preventing the same weaknesses during design and development.
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