Heap overflow in certificate regexp parsing — Mozilla

Moxie Marlinspike reported a heap overflow vulnerability in the code that handles regular expressions in certificate names. This vulnerability could be used to compromise the browser and run arbitrary code by presenting a specially crafted certificate to the client. This code provided compatibility with the non-standard regular expression syntax historically supported by Netscape clients and servers. With version 3.5 Firefox switched to the more limited industry-standard wildcard syntax instead and is not vulnerable to this flaw.