Neither. There are regexes that can be written in the common subset supported by (say) libpcre, RE2 and Hyperscan that will induce exponential backtracking with

Neither. There are regexes that can be written in the common subset supported by (say) libpcre, RE2 and Hyperscan that will induce exponential backtracking with libpcre but not with the other libraries. I'm not aware of any difference in terms of sanitisation or security.