The constructs that can contain code ((?{...}) and (??{...})) cannot be interpolated into a regexp by default. So as long as use re 'eval'; isn't used, they won't be able to execute arbitrary code.

However! It is possible for them to construct a regexp that will take until the death of the universe to process, causing a denial of service if left unchecked.

It's also possible to create a regexp that crashes Perl (by overflowing the stack, IIRC). That particular issue has been fixed in 5.10, I believe.

In reply to Re: how to restrict a regexp? by ikegami
in thread how to restrict a regexp? by tfoertsch

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