What is OWASP Top 10?

A regularly updated list of the ten most critical web application security risks, published by the Open Web Application Security Project to guide developers and security teams.

OWASP Top 10 — Definition & Overview • DeepSource

The OWASP Top 10 is a standard awareness document published by the Open Web Application Security Project (OWASP) that identifies the most critical security risks to web applications. Updated approximately every three to four years based on vulnerability data from hundreds of organizations, the Top 10 serves as a baseline for application security programs worldwide.

Current OWASP Top 10 (2021)

Rank	Category	Description
A01	Broken Access Control	Failures in enforcing user permissions
A02	Cryptographic Failures	Weak or missing encryption of sensitive data
A03	Injection	SQL, NoSQL, OS, and LDAP injection flaws
A04	Insecure Design	Missing or ineffective security controls in design
A05	Security Misconfiguration	Insecure default settings, incomplete configurations
A06	Vulnerable and Outdated Components	Using libraries with known CVEs
A07	Identification and Authentication Failures	Broken authentication mechanisms
A08	Software and Data Integrity Failures	Assuming integrity without verification
A09	Security Logging and Monitoring Failures	Insufficient detection of breaches
A10	Server-Side Request Forgery	Fetching URLs without validation

How the Top 10 is determined

OWASP collects vulnerability data from:

Application security companies
Bug bounty platforms
Security consultancies
Open source projects

This data is analyzed for frequency, exploitability, and impact. The methodology balances:

Incidence: How often the vulnerability appears
Exploitability: How easy it is to attack
Detectability: How easy it is to find
Technical impact: Damage potential

Using the OWASP Top 10

Development guidance: Each category includes prevention techniques. Developers use the Top 10 as a checklist during design and code review.

Security testing: SAST and DAST tools map their findings to OWASP categories. This helps teams understand which classes of vulnerabilities they're detecting.

Compliance: While not a compliance standard itself, many regulations (PCI DSS, HIPAA) reference OWASP. Demonstrating coverage of the Top 10 satisfies baseline security requirements.

Training: The Top 10 is a common foundation for developer security training. Each category links to CWE entries for detailed technical information.

Beyond the Top 10

OWASP publishes specialized Top 10 lists for other domains:

OWASP API Security Top 10: Specific to API vulnerabilities
OWASP Mobile Top 10: Mobile application risks
OWASP Cloud-Native Application Security Top 10
OWASP Machine Learning Security Top 10

These specialized lists address risks not covered in the general web application Top 10.

Common misconceptions

"Fixing the Top 10 means we're secure": The Top 10 represents the most common risks, not all risks. Applications may have vulnerabilities outside these categories.

"The Top 10 is a testing checklist": It's a risk awareness document. Comprehensive testing requires more detailed methodologies like the OWASP Testing Guide.

"Lower-ranked items are less important": All Top 10 items represent critical risks. Ranking reflects frequency and aggregate data, not severity in your specific context.