Heap-based buffer overflow in aswRdr.sys (aka the TDI RDR driver) in avast! Home and Professional 4.8.1356.0 allows local users to cause a denial of service (memory corruption) or possibly gain privileges via crafted arguments to IOCTL 0x80002024.
secunia.com/advisories/37368
www.efblog.net/2009/11/avast-aswrdrsys-kernel-pool-corruption.html
www.securityfocus.com/archive/1/507891/100/0/threaded
www.securityfocus.com/bid/37031
www.vupen.com/english/advisories/2009/3266
www.evilfingers.com/advisory/Advisory/Avast_aswRdr_sys_Kernel_Pool_Corruption_and_Local_Privilege_Escalation.php