VirtualBox 6.1.18 (released January 19 2021)
https://www.virtualbox.org/wiki/Changelog-6.1#v18

This is a maintenance release. The following items were fixed and/or added:

Nested VM: Fixed hangs when executing SMP nested-guests under certain conditions on Intel hosts (bug #19315, #19561)
OCI integration: Cloud Instance parameters parsing is improved on import (bug #19156)
Network: UDP checksum offloading in e1000 no longer produces zero checksums (bug #19930)
Network: Fixed Host-Only Ethernet Adapter DHCP, guest os can not get IP on host resume (bug #19620)
NAT: Fixed mss parameter handing (bug #15256)
macOS host: Multiple optimizations for BigSur
Audio: Fixed issues with audio playback after host goes to sleep (bug #18594)
Documentation: Some content touch-up and table formatting fixes
Linux host and guest: Support kernel version 5.10 (bug #20055)
Solaris host: Fix regression breaking VGA text mode since version 6.1.0
Guest Additions: Fixed a build failure affecting CentOS 8.2-2004 and later (bug #20091)
Guest Additions: Fixed a build failure affecting Linux kernels 3.2.0 through 3.2.50 (bug #20006)
Guest Additions: Fixed a VM segfault on copy with shared clipboard with X11 (bug #19226)
Shared Folder: Fixed error with remounting on Linux guests