Yesterday we published a diary about a new vulnerability and POC that affected Firefox 3.5.1.  Today we received a note from the good people at Mozilla with some clarification.  Here is what they said:

We do not believe this is any kind of boundary condition, but a
non-exploitable denial-of-service due to memory exhaustion.

Our bug for reference:
https://bugzilla.mozilla.org/show_bug.cgi?id=504342

Thanks for the update, Reed!

UPDATE 1:

Reed pointed us to the following Mozilla blog posting on this issue:

http://blog.mozilla.com/security/2009/07/19/milw0rm-9158-stack-overflow-crash-not-exploitable-cve-2009-2479/

Also, one of our readers points out that "...the PoC in Internet Explorer 8 throws a script exception stating that there is 'not enough storage to complete this operation'..."  I like the way our readers think - take malware designed to exploit one piece of software and throw it at another one to see what happens.  That's what makes security professionals different from regular system administrators...always tinkering, always looking for ways to break things.  :)

Marcus H. Sachs
Director, SANS Internet Storm Center