Problem with compiling Virtualbox modules, e.g.

SSL error:02001002:system library:fopen:No such file or directory: ../crypto/bio/bss_file.c:72
..

see also ticket

It seems that there is a version mismatch in /usr/src/linux-headers-5.4.0-52-generic/include/config/kernel.release and the actual kernel version that is running, e.g. 5.4.65 vs 5.4.0-52-generic.

Changing the version in kernel.release to the actual kernel version number fixes the problem with vboxconfig.