Re: New Flaw in Firefox 2.0: DoS and possible remote code execution

[Daniel Veditz <dveditz () cruzio com>]

xxxx () gmail com wrote:
> When you have a NULL pointer dereference a code execution is also possible, so you can't exclude it at all.
> For example in this old flaw:
> http://securitytracker.com/alerts/2006/Apr/1016001.html

In that example there was a way to influence the crash so that it was not null.
The Metasploit blog previously reported on a way to use a null dereference crash
to trigger a vulnerability in the windows SEH to run code (since fixed, and not
exploitable via Firefox as far as anyone can tell).

Neither of those conditions apply here, it's just a null dereference. In a debug
build you get

###!!! ASSERTION: Parsing didn't create a parser context?: 'mParserContext',
file c:/dev/ff2/mozilla/parser/htmlparser/src/nsParser.cpp, line 1882

This bug appears to have been fixed in the code that will become Firefox 3. This
crash is being tracked at https://bugzilla.mozilla.org/show_bug.cgi?id=358797