FreeBSD Security Advisory – The implementation of the TIOCGSERIAL ioctl(2) does not clear the output struct before copying it out to userland. The implementation of the Linux sysinfo() system call does not clear the output struct before copying it out to userland. An unprivileged user can read a portion of uninitialised kernel stack data, which may contain sensitive information, such as the stack guard, portions of the file cache or terminal buffers, which an attacker might leverage to obtain elevated privileges.