Regex Security Checker
Analyze regular expressions for ReDoS vulnerabilities and performance issues
Regular Expression
//
Examples:
About ReDoS Vulnerabilities
What is ReDoS?
Regular expression Denial of Service (ReDoS) occurs when a regex takes exponential time to evaluate certain inputs, causing CPU exhaustion.
Common Patterns
Nested quantifiers like (a+)+ or overlapping alternations like (a|a)* can cause catastrophic backtracking with malicious input.
Prevention
Use atomic groups, possessive quantifiers, or limit input length. Consider using RE2 for untrusted input patterns.
Real Impact
ReDoS has affected major platforms including Cloudflare, Stack Overflow, and npm package downloads.