The nfs4_proc_lock function in fs/nfs/nfs4proc.c in the NFSv4 client in the Linux kernel before 2.6.31-rc4 allows remote NFS servers to cause a denial of service (NULL pointer dereference and panic) by sending a certain response containing incorrect file attributes, which trigger attempted use of an open file that lacks NFSv4 state.

The sysctl functionality (sysctl.c) in Linux kernel before 2.6.14.1 allows local users to cause a denial of service (kernel oops) and possibly execute code by opening an interface file in /proc/sys/net/ipv4/conf/, waiting until the interface is unregistered, then obtaining and modifying function pointers in memory that was used for the ctl_table.