ReDoS
What this is
(a+)+b on a long string of aaaaaaaaaac is the textbook hang. Node's default regex is backtracking. Mitigate with input length limits, timeouts (Node vm / worker), rewriting to linear patterns, or RE2/Rust regex. This tester flags nested quantifiers with a warning; it is heuristic, not a proof.
FAQ
- Is my email regex safe?
- Many published email patterns are ReDoS vectors. Prefer a simple shape check plus confirmation email.