So far, the suggested hint is towards cups[0] which is a printing system for unix. I am not sure if it's even installed on all the distros by default
the title claims "all" GNU/Linux systems are vulnerable
As such, every single thing about the topic should be taken with a grain of salt. Starting with systems affected (it's not all GNU/Linux) and also CVSS score (I score it as a 6.3 instead of 9.9). Use your imagination to decide how much of what was posted is based on fact as opposed to fantasy.