According to Intel, there is a buffer overflow in the drivers for one of their most popular NICs that can be used to escalate privilege locally.  The flaw affects drivers for Intel PRO 10/100 adapters on Windows (>=Win2K), Linux, and UnixWare platforms.  A complete listing of affected driver versions can be found here.

(Note: Thanks to everyone who pointed out that we needed to add an equals sign to the Windows description.)