In Yarn before 1.21.1, the package install functionality can be abused to generate arbitrary symlinks on the host filesystem by using specially crafted "bin" keys. Existing files could be overwritten depending on the current user permission set.
Red Hat Security Advisory 2020-0475-01 - An update is now available for Red Hat Quay 3. An issue where install functionality in nodejs-yarn could be abused has been addressed.