If you have a dedicated server then you need to check that your kernel is patched for Meltdown+Spectre v2.
https://meltdownattack.com
There are nasties in the wild now exploiting these vulnerabilities at scale.
If you are self managed then patch and recompile your kernel. Some providers have pre-patched kernels - eg: on OVH install the Vanilla kernel which is prepatched and included microcodes.
If you are not self managed and have a managed service then get on to your provider and make sure they can demonstrate to you your server is patched properly.
Initially these attacks were proof of concept only, there are reports from security professionals that in the wild attacks have been seen escalating recently.
This is really important to fix. Check your systems out.