The OWASP Top 10 is a widely used awareness standard for the most important web application security risks. It gives development, security and risk teams a shared language for improving design, testing and remediation.
This guide reflects the current OWASP Top 10 release. It should be used as a baseline—not as a complete application security program—alongside threat modeling, secure development practices, code review, testing and continuous monitoring.
The OWASP Top 10 web application security risks
A01 — Broken Access Control
Access-control weaknesses allow users to act outside their intended permissions—for example, viewing another user’s data, modifying protected records or invoking administrative functions. Authorization must be enforced server-side, deny by default and be tested for every relevant role and object.
A02 — Security Misconfiguration
Insecure defaults, unnecessary services, verbose errors, missing hardening and inconsistent settings can expose an otherwise sound application. Organizations need repeatable configuration baselines, automated checks and controlled changes across every environment.
A03 — Software Supply Chain Failures
Applications depend on packages, build systems, repositories and delivery pipelines that can introduce risk. Teams should know what they use, protect build and release processes, verify provenance and signatures, monitor dependencies and respond quickly to compromised components.
A04 — Cryptographic Failures
Sensitive data can be exposed when encryption is missing, obsolete or incorrectly implemented. Strong algorithms are only part of the solution: key management, transport protection, data minimization and secure handling throughout the lifecycle are equally important.
A05 — Injection
Injection occurs when untrusted input is interpreted as a command or query. Parameterized interfaces, contextual output encoding, input validation and separation between data and instructions reduce the risk across SQL, operating-system commands, templates and other interpreters.
A06 — Insecure Design
Some weaknesses originate in the design rather than in an implementation bug. Threat modeling, abuse-case analysis, secure design patterns and explicit security requirements are needed before code-level controls can be effective.
A07 — Authentication Failures
Weak identity verification, credential handling or session management can enable account takeover. Multi-factor authentication, secure recovery, protection against automated attacks and robust session controls should be applied according to risk.
A08 — Software or Data Integrity Failures
Systems fail when they trust software, updates, plugins or critical data without verifying integrity. Use trusted sources, signed artifacts, protected update mechanisms and careful handling of serialized or externally supplied data.
A09 — Security Logging and Alerting Failures
Without meaningful logs, monitoring and actionable alerts, attacks can remain undetected and investigations become unreliable. Record security-relevant events, protect log integrity, define response thresholds and regularly test that alerts reach the right people.
A10 — Mishandling of Exceptional Conditions
Unexpected inputs, timeouts, resource exhaustion and partial failures can push applications into unsafe states. Systems should fail securely, handle errors consistently, limit resource consumption and avoid exposing sensitive internal details.
How organizations should use the OWASP Top 10
Use the list to inform security requirements, architecture reviews, developer training, code review and penetration testing. Then extend it with application-specific threat modeling, business-impact analysis and controls for APIs, cloud services, identity, supply chains and operational resilience.
Official reference: OWASP Top 10. For dynamic application testing, OWASP ZAP is available at zaproxy.org.
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About the author
Oscar Calvo Moldes is a cybersecurity professional with more than 25 years of hands-on experience. He is Co-founder and CTO at Axyom, Founder of MicroHackers, and currently focuses on AI/LLM security.
