/usr/lib/x86_64-linux-gnu/libcholmod.so.3 is in libcholmod3 1:5.1.2-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libcholmod.so.3.0.11
/usr/lib/x86_64-linux-gnu/libcholmod.so.3.0.11