Internet Explorer MSXML3 Race Condition Memory Corruption Vulnerability
Microsoft Internet Explorer is prone to a remote memory-corruption vulnerability because of a race condition that may cause a NULL-pointer dereference, read or write operations to invalid addresses, or other memory-corruption issues.
Attackers may likely exploit this issue to execute arbitrary machine code in the context of the vulnerable application, but this has not been confirmed. Failed exploit attempts will likely crash the application.
Affected version is the v6 SP2 and earlier of Internet Explorer. More at http://www.securityfocus.com/bid/21872/discuss