Linux VServer 1.27 and earlier, 1.3.9 and earlier, and 1.9.1 and earlier shares /proc permissions across all virtual and host servers, which allows local users with the ability to set permissions in /proc to obtain system information or cause a denial of service on other virtual servers or the host server.

Linux-VServer 1.24 allows local users with root privileges on a virtual server to gain access to the filesystem outside the virtual server via a modified chroot-again exploit using the chmod command.

Race condition in the setsid function in Linux before 2.6.8.1 allows local users to cause a denial of service (crash) and possibly access portions of kernel memory, related to TTY changes, locking, and semaphores.