Cascade Regex Pattern Causes Performance Catastrophe
Application becomes unresponsive after Cascade generated a complex regex pattern for validation. Regex matching against certain inputs takes seconds or minutes, consuming 100% CPU. This is a Regular Expression Denial of Service (ReDoS) vulnerability.
Cascade likely generated a regex with catastrophic backtracking.
Error Messages You Might See
Common Causes
- Cascade generated overlapping alternations: (a+)+, (a|a)+, (.*)*
- Nested quantifiers causing exponential backtracking
- Pattern with many alternatives and backtracking on failure
How to Fix It
Identify problematic regex in error logs or profiling. Use online regex performance tools. Replace complex regex with simpler patterns or direct validation logic. Add input length limits before regex matching. Test regex with worst-case inputs. Use atomic grouping (?>...) to prevent backtracking.
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Get HelpFrequently Asked Questions
What patterns cause ReDoS?
Nested quantifiers: (a+)+, (a*)*. Overlapping alternations: (a|a)+. Avoid these patterns.
How do I test regex safety?
Use regex101.com with performance tests. Try matching intentionally bad input. Check time complexity.