Catastrophic regex backtracking

A regex with pathological quantifiers exhibits exponential runtime on crafted inputs (ReDoS).

Rewrite patterns to avoid nested backtracking; add input length limits/timeouts; prefer linear-time engines where available

Observable signs that may indicate Catastrophic regex backtracking:

• Requests hang or CPU spikes on specific input strings.
• Regex evaluation dominates profiles under load.
• DoS-like behavior with crafted repeating patterns.