DeepFrontend
Learning Paths
Practice
System Design & DS
Design Studio
Data Structures Curriculum
Real-World Case Studies
Careers
Job Board
Resume Builder
Blog
Sign in
Search
⌘K
Go Pro
Loading compiler resources...
Web Security Quiz Practice
Active Recall Drill Session
← Exit Session
Question 1 of 1
medium
Web Security
Why is denylisting patterns like <script> tags an unreliable XSS defense?
A
It's actually a complete, reliable defense
B
There are many other executable sinks (onerror, onload, javascript: URLs, svg onload) that don't contain <script> at all, so a denylist reliably misses some
C
Denylisting is slower than allowlisting
D
Browsers ignore denylist filtering entirely
Check Answer