The nfs_permission function in fs/nfs/dir.c in the NFS client implementation in the Linux kernel 2.6.29.3 and earlier, when atomic_open is available, does not check execute (aka EXEC or MAY_EXEC) permission bits, which allows local users to bypass permissions and execute files, as demonstrated by files on an NFSv4 fileserver.
nfsd in the Linux kernel before 2.6.28.9 does not drop the CAP_MKNOD capability before handling a user request in a thread, which allows local users to create device nodes, as demonstrated on a filesystem that has been exported with the root_squash option.
The icmp_send function in net/ipv4/icmp.c in the Linux kernel before 2.6.25, when configured as a router with a REJECT route, does not properly manage the Protocol Independent Destination Cache (aka DST) in some situations involving transmission of an ICMP Host Unreachable message, which allows remote attackers to cause a denial of service (connectivity outage) by sending a large series of packets to many destination IP addresses within this REJECT route, related to an "rt_cache leak."
parse.c in sudo 1.6.9p17 through 1.6.9p19 does not properly interpret a system group (aka %group) in the sudoers file during authorization decisions for a user who belongs to that group, which allows local users to leverage an applicable sudoers file and gain root privileges via a sudo command.