The Linux kernel before 2.6.25.10 does not properly perform tty operations, which allows local users to cause a denial of service (system crash) or possibly gain privileges via vectors involving NULL pointer dereference of function pointers in (1) hamradio/6pack.c, (2) hamradio/mkiss.c, (3) irda/irtty-sir.c, (4) ppp_async.c, (5) ppp_synctty.c, (6) slip.c, (7) wan/x25_asy.c, and (8) wireless/strip.c in drivers/net/.