An unprivileged user could exploit this vulnerability on default installations of Ubuntu 20.04, Ubuntu 20.10, Ubuntu 21.04, Debian 11, and Fedora 34 Workstation. Other Linux distributions are likely vulnerable and probably exploitable. Users should apply the patches as soon as possible as this vulnerability

The Qualys Research Team has discovered a size_t-to-int type conversion vulnerability in the Linux Kernel’s filesystem layer affecting most Linux operating systems. Any unprivileged user can gain root privileges on a vulnerable host by exploiting this vulnerability in a default configuration.

[blog.qualys.com...]