Describe CVE-2021-28117.
What is CVE-2021-28117?
libdiscover/backends/KNSBackend/KNSResource.cpp in KDE Discover before 5.21.3 automatically creates links to potentially dangerous URLs (that are neither https:// nor http://) based on the content of the store.kde.org web site. (5.18.7 is also a fixed version.).