The pppol2tp_recvmsg function in drivers/net/pppol2tp.c in the Linux kernel 2.6 before 2.6.26-rc6 allows remote attackers to cause a denial of service (kernel heap memory corruption and system crash) and possibly have unspecified other impact via a crafted PPPOL2TP packet that results in a large value for a certain length variable.

More... (http://nvd.nist.gov/nvd.cfm?cvename=CVE-2008-2750)