Common Web Vulnerabilities Explained

Most web application breaches don't come from exotic zero-days — they come from the same handful of flaws showing up in slightly different clothes. Knowing this list well is worth more than knowing ten obscure exploits.

Injection flaws

SQL injection, command injection, and their relatives all share one root cause: user input that gets treated as code instead of data. Parameterized queries and strict input handling close the door on most of them.

Cross-site scripting (XSS)

When untrusted input gets rendered back into a page without proper encoding, an attacker can run script in another user's browser — stealing sessions, defacing pages, or pivoting to worse things.

Broken access control

This is consistently one of the most common findings in real assessments: an endpoint that checks whether you're logged in, but not whether you're allowed to see this record. Simple to describe, easy to miss, costly when exploited.

• Learn to recognize these patterns by category, not just by tool output.
• Understand the fix, not just the exploit — that's what separates a tester from a script runner.
• The OWASP Top 10 is a map, not a checklist to memorize and forget.