The OWASP Top 10 is one of the most widely recognized resources for understanding web application security risks. Developed by the Open Worldwide Application Security Project (OWASP), the list identifies critical vulnerabilities that organizations should understand, assess, and address to strengthen their application security posture.
As web applications become increasingly complex, security risks continue to evolve. Cloud-based infrastructure, third-party software dependencies, application programming interfaces (APIs), and increasingly interconnected systems have expanded the potential attack surface for organizations. Vulnerabilities that once affected individual applications can now expose entire environments to unauthorized access, data breaches, and operational disruption.
The OWASP Top 10 helps organizations understand these risks and establish priorities for application security testing. However, the list is not an exhaustive catalogue of every vulnerability that could affect an application. Organizations must look beyond the Top 10 to identify weaknesses specific to their technology, architecture, business processes, and threat environment.
This guide examines the OWASP Top 10, compares the 2021 and 2025 editions, and explains how organizations can use the findings to improve web application security through penetration testing and secure software development practices.
What Is the OWASP Top 10?
OWASP is a nonprofit foundation dedicated to improving software security through open-source projects, community-driven research, educational resources, and practical security guidance. Its mission is to help organizations develop, acquire, operate, and maintain applications that can be trusted.
The OWASP Top 10 is an awareness document that identifies some of the most critical web application security risks based on industry research and contributions from security professionals worldwide.
The project has become an important reference for developers, application security teams, penetration testers, and organizations responsible for protecting web applications. It provides a common framework for discussing security risks and helps organizations identify areas that require additional attention.
The OWASP Top 10 is updated periodically to reflect changes in application architectures, attack techniques, vulnerability research, and industry practices. The 2017 edition established a foundation that was refined in 2021, with further changes introduced in the 2025 edition.
Other OWASP initiatives complement the Top 10, including the OWASP Mobile Top 10 and the OWASP Top 10 Proactive Controls. These resources address different aspects of application security and can help organizations develop a more comprehensive approach to reducing risk.
What Is the Purpose of the OWASP Top 10?
The primary purpose of the OWASP Top 10 is to raise awareness of significant application security risks and encourage organizations to address them before attackers can exploit them.
Web application vulnerabilities can expose sensitive information, compromise user accounts, disrupt business operations, and provide attackers with a foothold in an organization's broader network. Identifying and remediating these weaknesses is therefore an essential component of an effective cybersecurity strategy.
The OWASP Top 10 helps organizations:
Identify common and critical web application security risks.
Establish priorities for application security testing and remediation.
Improve secure coding practices throughout the software development lifecycle.
Educate developers, security professionals, and business stakeholders about application security.
Evaluate whether existing security controls address important vulnerability categories.
Develop a shared vocabulary for communicating application security risks.
However, OWASP emphasizes that organizations should not stop at the Top 10. The list is an awareness document, not a comprehensive testing checklist or guarantee of application security.
A web application can contain serious vulnerabilities that do not fit neatly into one of the ten categories. Business logic flaws, application-specific authorization weaknesses, insecure workflows, and complex attack chains may require specialized testing to identify.
Organizations should therefore use the OWASP Top 10 as a starting point for application security assessments rather than treating it as the complete scope of their security program.
OWASP Top 10 2021: Security Risks and Key Findings
The OWASP Top 10 2021 introduced three new categories, revised the scope of several existing categories, and incorporated lessons from industry testing data and a community survey.
The 2021 edition placed greater emphasis on the underlying causes of vulnerabilities rather than focusing exclusively on their consequences. For example, the former category Sensitive Data Exposure was renamed Cryptographic Failures to highlight weaknesses in the security mechanisms intended to protect sensitive information.
According to OWASP, Broken Access Control was the most significant risk in the 2021 edition. The project also identified concerns involving insecure software design, software integrity, and server-side request forgery. (GitHub)
The following are the ten categories in the OWASP Top 10 2021.
A01:2021 – Broken Access Control
Broken Access Control ranked first in the 2021 edition, moving up from fifth place in 2017. This category addresses vulnerabilities that allow users to access information or perform actions beyond their authorized permissions.
Examples include accessing another user's account by modifying a URL, viewing restricted records, or performing administrative functions without the necessary privileges.
OWASP reported that an average of 3.81% of applications tested had at least one instance of a mapped weakness in this category. The category also accounted for more than 318,000 reported occurrences of mapped Common Weakness Enumerations (CWEs) in the contributed data. (GitHub)
Organizations should implement server-side authorization checks, apply least-privilege principles, and test access controls across different user roles.
A02:2021 – Cryptographic Failures
Previously associated with Sensitive Data Exposure, Cryptographic Failures focuses on weaknesses in the protection of sensitive information.
These vulnerabilities can arise when applications use outdated cryptographic algorithms, transmit sensitive information without adequate encryption, or store passwords and confidential data insecurely.
Potential consequences include the exposure of personal information, financial records, authentication credentials, and proprietary business data.
Organizations should use appropriate encryption, secure key management practices, and modern transport security protocols. They should also verify that sensitive information is not unnecessarily collected, retained, or exposed.
A03:2021 – Injection
Injection vulnerabilities occur when untrusted input is interpreted as commands or queries rather than ordinary data.
Examples include SQL injection, operating system command injection, and cross-site scripting (XSS), which OWASP incorporated into this category in 2021.
An attacker may exploit an injection vulnerability to access database records, manipulate application behavior, or execute malicious scripts in a user's browser.
OWASP reported an average incidence rate of 3.37% across the tested applications for the mapped injection weaknesses. It also noted that 94% of applications in the contributed data had been tested for some form of injection. (GitHub)
Developers can reduce these risks through parameterized queries, appropriate output encoding, input validation, and secure API design.
A04:2021 – Insecure Design
Insecure Design was introduced in the 2021 edition to address weaknesses that originate in an application's architecture, requirements, or business logic.
Unlike implementation flaws, design weaknesses can exist even when developers write code correctly. If an application does not include the controls necessary to prevent abuse, fixing individual coding errors may not resolve the underlying problem.
For example, an online payment application may allow users to repeat a transaction or bypass a business rule because the original workflow was not designed to prevent those actions.
Organizations should incorporate threat modeling, abuse-case analysis, secure design principles, and security requirements into the software development lifecycle.
A05:2021 – Security Misconfiguration
Security Misconfiguration moved from sixth place in 2017 to fifth place in 2021.
This category includes insecure default settings, unnecessary services, improperly configured permissions, exposed administrative interfaces, and verbose error messages that reveal sensitive information.
Misconfigurations can affect application code, web servers, cloud infrastructure, databases, and supporting services.
OWASP reported that 90% of the applications in its contributed data had been tested for some form of misconfiguration. The average incidence rate for the mapped weaknesses was 4.5%. (GitHub)
Organizations should establish secure configuration baselines, remove unnecessary functionality, regularly review cloud permissions, and verify configurations after software updates.
A06:2021 – Vulnerable and Outdated Components
Modern applications depend on third-party libraries, frameworks, and other software components. When these dependencies contain known vulnerabilities or are no longer maintained, attackers may be able to exploit them.
Organizations may not always know which components their applications use, whether those components are affected by known vulnerabilities, or whether security updates are available.
Effective mitigation includes maintaining a software inventory, monitoring vulnerability disclosures, updating dependencies, and prioritizing remediation based on exploitability and business impact.
A07:2021 – Identification and Authentication Failures
Identification and Authentication Failures addresses weaknesses in verifying user identities and managing authentication sessions.
Examples include weak passwords, ineffective multifactor authentication, insecure password recovery processes, and session management flaws.
Attackers may exploit these weaknesses to take over accounts, impersonate legitimate users, or access restricted application functions.
Organizations should implement secure authentication mechanisms, enforce appropriate session controls, protect password reset workflows, and monitor suspicious login activity.
A08:2021 – Software and Data Integrity Failures
This category addresses situations in which applications fail to verify the integrity of software, updates, or critical data.
Examples include accepting untrusted software updates, using insecure deserialization, and allowing unauthorized changes to development or deployment pipelines.
These weaknesses can enable attackers to introduce malicious code or manipulate information that the application trusts.
Organizations should verify software signatures where appropriate, secure build pipelines, restrict access to deployment systems, and validate the integrity of critical data.
A09:2021 – Security Logging and Monitoring Failures
Security Logging and Monitoring Failures concerns inadequate logging, insufficient monitoring, and ineffective incident detection.
When applications fail to record relevant security events or alert responders to suspicious activity, attackers may remain undetected for extended periods.
Effective logging should capture important events without unnecessarily exposing sensitive information. Monitoring systems should also generate actionable alerts and support incident investigation.
Organizations should regularly test their detection capabilities and ensure that security teams can investigate suspicious behavior using reliable application and infrastructure logs.
A10:2021 – Server-Side Request Forgery (SSRF)
Server-Side Request Forgery occurs when an application can be manipulated into making unauthorized requests to other systems.
For example, an attacker may abuse a feature that retrieves external URLs to access internal services that are not directly accessible from the internet.
Depending on the environment, SSRF may expose internal resources, sensitive metadata, or services that trust requests originating from the application server.
OWASP included SSRF as a distinct category in 2021 following strong community concern, despite its relatively low incidence in the available data. This illustrates why the Top 10 considers expert input alongside observed vulnerability statistics. (GitHub)
Mitigations include restricting outbound requests, validating destinations, blocking access to sensitive internal address ranges, and applying appropriate network segmentation.
OWASP Top 10 2025: Security Risks and Key Findings
The OWASP Top 10 2025 is the current edition of the project, superseding the 2021 list. It reflects changes in application security research, testing data, and industry concerns.
The 2025 edition retains several familiar categories but changes their rankings and scope. Two new categories appear: Software Supply Chain Failures and Mishandling of Exceptional Conditions. Server-Side Request Forgery is incorporated into Broken Access Control, while Security Logging and Monitoring Failures is renamed Security Logging and Alerting Failures. (OWASP Top 10)
The following sections explain each category and its implications for application security.
A01:2025 – Broken Access Control
Broken Access Control remains in first place, reinforcing the importance of enforcing permissions consistently across web applications.
The category now incorporates Server-Side Request Forgery, which was listed separately in 2021. OWASP reported that an average of 3.73% of applications tested had one or more of the 40 CWEs included in this category. (OWASP Top 10)
Organizations should test for unauthorized access to records, privilege escalation, insecure direct object references, and weaknesses in server-side request restrictions.
A02:2025 – Security Misconfiguration
Security Misconfiguration moved from fifth place in 2021 to second place in 2025.
As applications become more configurable and rely on increasingly complex infrastructure, configuration errors can create significant security weaknesses. These may include exposed services, insecure permissions, unnecessary features, and incorrect security settings.
OWASP reported that 3.00% of applications tested had at least one of the 16 CWEs mapped to this category. (OWASP Top 10)
Organizations should establish secure configuration standards, automate configuration checks where practical, and regularly review application and infrastructure settings.
A03:2025 – Software Supply Chain Failures
Software Supply Chain Failures is a new category in the 2025 edition. It expands beyond the 2021 category Vulnerable and Outdated Components to address compromises throughout the software ecosystem.
Risks may originate in third-party dependencies, build systems, development tools, software distribution mechanisms, and other elements involved in creating or delivering software.
A compromised dependency or build pipeline can introduce malicious code into otherwise legitimate applications.
OWASP identified this category as a major community concern. Although the collected data showed relatively few occurrences, the associated vulnerabilities had the highest average exploit and impact scores from the mapped CVEs. OWASP also cautioned that testing limitations may contribute to the low observed occurrence rate. (OWASP Top 10)
Organizations should maintain software bills of materials where appropriate, verify dependencies, restrict access to build systems, and establish processes for evaluating supplier security.
A04:2025 – Cryptographic Failures
Cryptographic Failures moved from second place in 2021 to fourth place in 2025.
The category includes weaknesses that undermine the confidentiality or integrity of sensitive information, including inadequate encryption, insecure key management, and inappropriate cryptographic implementations.
OWASP reported that an average of 3.80% of applications tested had at least one of the 32 CWEs mapped to this category. (OWASP Top 10)
Organizations should evaluate how sensitive data is collected, transmitted, stored, and deleted. They should also review encryption standards, certificate management, and access to cryptographic keys.
A05:2025 – Injection
Injection moved from third place in 2021 to fifth place in 2025.
The category continues to include weaknesses that allow untrusted input to alter the behavior of commands or queries. Examples include SQL injection, command injection, and cross-site scripting.
OWASP notes that injection remains a frequently tested category and includes a substantial number of mapped CVEs. Its scope encompasses vulnerabilities with different combinations of frequency, exploitability, and potential impact. (OWASP Top 10)
Organizations should use parameterized queries, context-appropriate output encoding, input validation, and secure development practices. Testing should also consider whether injection weaknesses can be combined with other vulnerabilities to achieve a more serious outcome.
A06:2025 – Insecure Design
Insecure Design moved from fourth place in 2021 to sixth place in 2025.
The category focuses on weaknesses that arise when security requirements and protections are missing from an application's design.
Examples include workflows that allow business rules to be bypassed, insufficient abuse prevention, and application architectures that fail to account for realistic attack scenarios.
OWASP noted improvements in industry practices involving threat modeling and secure design, although these weaknesses remain important. (OWASP Top 10)
Organizations should define security requirements early, evaluate misuse scenarios, and validate important business rules through manual security testing.
A07:2025 – Authentication Failures
Authentication Failures retains seventh place, with a shorter name than the 2021 category Identification and Authentication Failures.
This category covers weaknesses that allow attackers to impersonate legitimate users or compromise accounts.
Examples include weak authentication mechanisms, insecure session handling, and ineffective account recovery processes.
OWASP suggests that the increased use of standardized authentication frameworks may be contributing to improvements in this area. However, organizations must still verify that authentication controls are correctly implemented and configured. (OWASP Top 10)
A08:2025 – Software or Data Integrity Failures
Software or Data Integrity Failures remains in eighth place.
The category focuses on failures to verify the integrity and trustworthiness of software, code, and data. It includes weaknesses involving updates, deserialization, and processes that accept untrusted artifacts without sufficient validation.
Although this category overlaps with Software Supply Chain Failures, the distinction is important. Software Supply Chain Failures addresses broader compromises across the software ecosystem, while Software or Data Integrity Failures focuses on failures to establish or maintain trust in software and data.
Organizations should verify software artifacts, protect deployment pipelines, and validate data received from untrusted sources.
A09:2025 – Security Logging and Alerting Failures
This category remains in ninth place but changes its name from Security Logging and Monitoring Failures.
The updated terminology emphasizes that collecting logs is not enough. Organizations must also detect relevant events and generate alerts that prompt an appropriate response.
For example, an application may record repeated unauthorized access attempts but provide no alert to the security team. Without effective detection and escalation, suspicious activity may continue unnoticed.
Organizations should establish meaningful security logging, configure actionable alerts, protect log integrity, and test incident response procedures. (OWASP Top 10)
A10:2025 – Mishandling of Exceptional Conditions
Mishandling of Exceptional Conditions is a new category in the 2025 edition.
It addresses weaknesses involving improper error handling, logical errors, and unexpected application behavior when systems encounter abnormal conditions.
Examples include applications failing open when a security check encounters an error, exposing sensitive information through error messages, or processing transactions incorrectly when an operation fails partway through.
These weaknesses can undermine security controls even when an application performs correctly under normal conditions.
OWASP identifies 24 CWEs within this category. Organizations should test how applications respond to invalid inputs, service failures, interrupted transactions, and unexpected system states. Error handling should fail securely, preserve data integrity, and avoid disclosing sensitive implementation details. (OWASP Top 10)
OWASP Top 10 2021 vs. 2025: What Changed?
Comparing the two editions reveals how application security priorities have evolved. Although several categories remain consistent, the 2025 edition places greater emphasis on software supply chain security, configuration management, and the handling of unexpected application conditions.
The most significant changes include:
Broken Access Control remains the leading risk, demonstrating the importance of effective authorization controls.
Security Misconfiguration rises from fifth to second place.
Software Supply Chain Failures replaces Vulnerable and Outdated Components with a broader focus on software ecosystem risks.
Server-Side Request Forgery is consolidated into Broken Access Control.
Mishandling of Exceptional Conditions introduces greater emphasis on secure error handling and unexpected application behavior.
Security Logging and Alerting Failures emphasizes the importance of generating actionable alerts rather than simply collecting logs.
These changes reflect the evolving nature of application development and the need to assess more than traditional coding vulnerabilities. (OWASP Top 10)
Organizations should review their application security programs against the 2025 edition while retaining relevant historical findings from earlier assessments. A vulnerability that does not appear as a standalone category in the latest list may still present a significant risk.
How Do You Test Web Applications Against the OWASP Top 10?
Understanding the OWASP Top 10 is an important first step, but organizations must also determine whether their applications contain these vulnerabilities.
Web application penetration testing helps identify security weaknesses by evaluating applications from an attacker's perspective. Qualified security professionals use a combination of manual techniques and automated tools to assess vulnerabilities, validate potential attack paths, and determine the potential business impact of successful exploitation.
A comprehensive assessment should consider the OWASP Top 10 alongside application-specific risks, business logic, and the organization's broader threat environment.
Automated and Manual Application Security Testing
Automated tools can efficiently identify common vulnerabilities, known software weaknesses, and certain configuration problems. They are valuable for repeatable testing and continuous integration into development workflows.
However, automated scanning alone cannot reliably identify every vulnerability. Complex authorization issues, business logic flaws, and vulnerabilities that require multiple steps to exploit often need manual investigation.
Combining automated scanning with expert-led manual testing provides a more complete understanding of application security risks.
Organizations can also incorporate static and dynamic application security testing into their software development lifecycle.
Static application security testing (SAST) examines source code or other representations of an application without requiring the application to run. It can help developers identify insecure coding patterns early in development.
Dynamic application security testing (DAST) evaluates a running application to identify vulnerabilities observable during execution. It can reveal weaknesses involving application behavior, server configuration, authentication, and responses to malicious input.
Neither approach provides complete coverage independently. Organizations should select testing methods based on their application architecture, development practices, and security requirements.
Why Penetration Testing Should Go Beyond the OWASP Top 10
The OWASP Top 10 is a useful reference, but it should not define the entire scope of a penetration test.
Applications may contain unique vulnerabilities that depend on their business logic, integrations, user permissions, and operational requirements. Attackers may also chain multiple lower-severity weaknesses together to achieve a more significant impact.
A thorough penetration test should evaluate the OWASP Top 10 while investigating additional vulnerabilities relevant to the application and its environment.
Organizations should also prioritize findings according to exploitability, potential impact, exposure, and business context. Not every vulnerability presents the same level of risk, and remediation efforts should reflect the consequences of successful exploitation.
Working with a qualified penetration testing provider can help organizations identify weaknesses that automated tools and routine security checks may overlook.
Frequently Asked Questions About the OWASP Top 10
What is the latest OWASP Top 10?
The OWASP Top 10 2025 is the latest released edition. It updates the 2021 list to reflect changes in application security risks, industry research, and community feedback. The 2025 edition introduces Software Supply Chain Failures and Mishandling of Exceptional Conditions as new categories.
What are the differences between OWASP Top 10 2021 and 2025?
The 2025 edition retains several categories but changes their rankings and scope. Security Misconfiguration rises from fifth to second place, Software Supply Chain Failures expands the scope of component-related risks, and Server-Side Request Forgery becomes part of Broken Access Control. The 2025 list also introduces Mishandling of Exceptional Conditions.
Is the OWASP Top 10 a comprehensive security checklist?
No. The OWASP Top 10 is an awareness document that identifies important application security risks. It is not an exhaustive list of all possible vulnerabilities, nor does compliance with its categories guarantee that an application is secure. Organizations should supplement it with comprehensive application security testing.
How often is the OWASP Top 10 updated?
OWASP updates the list periodically as application security risks, testing methodologies, and industry practices evolve. The 2021 and 2025 editions illustrate how the categories change over time. Organizations should consult the official OWASP project for the latest edition.
How can organizations test for OWASP Top 10 vulnerabilities?
Organizations can use a combination of automated vulnerability scanning, static and dynamic application security testing, code reviews, and manual penetration testing. Manual testing is particularly valuable for identifying complex authorization weaknesses, business logic flaws, and attack paths that automated tools may miss.
Does passing an OWASP Top 10 assessment mean an application is secure?
No. Testing against the OWASP Top 10 helps organizations identify important vulnerabilities, but it cannot establish that an application is completely secure. Additional testing should address application-specific risks, business logic, infrastructure, integrations, and other potential attack vectors.
Conclusion: Strengthen Application Security With OWASP Top 10 Testing
The OWASP Top 10 remains an essential starting point for organizations looking to understand and address web application security risks. Comparing the 2021 and 2025 editions demonstrates how application security priorities evolve as software architectures, development practices, and attack techniques change.
Broken Access Control remains a leading concern, while the latest edition highlights the growing importance of secure configuration, software supply chain protection, and appropriate handling of exceptional conditions.
However, organizations should not treat the OWASP Top 10 as a complete application security strategy. Effective protection requires ongoing security testing, secure development practices, and a clear understanding of how vulnerabilities could affect business operations.
At Packetlabs, our penetration testing team assesses applications across a range of industries to identify vulnerabilities, validate potential attack paths, and help organizations understand their security risks. Our approach goes beyond identifying individual weaknesses to examine how vulnerabilities may affect the broader environment.
By combining expert-led testing with established security frameworks, organizations can make more informed remediation decisions and strengthen their application security posture.
To learn more about how Packetlabs can help identify vulnerabilities in your web applications, contact our team to discuss your security testing requirements.
