Magento-lts is a long-term support alternative to Magento Community Edition (CE). Prior to version 20.16.1, the admin url can be discovered without prior knowledge of it's location by exploiting the X-Original-Url header on some configurations. This issue has been patched in version 20.16.1.
Exploitability
AV:NAC:LPR:NUI:NScope
S:UImpact
C:LI:NA:N5.3/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:NInformation Disclosure