Kernel panics can be caused by many things. Many times it is failing hardware, but System-level software drivers and extensions can cause them too.
I noticed from your log, that you are running macOS 10.13.3 High Sierra. I would recommend the following:
1. Make sure you have a current Time Machine or other backup of you data.
2. Update to macOS 10.13.6 High Sierra, which will update Safari as well.
3. Check if you have any Safari Extensions loaded, and let us know what they are.
4. Check if you have any Login Items, and let us know what they are.
5. Do you have any third-party utilities like MacKeeper or antivirus installed?
6. Feel free to post the entire panic log, so we can troubleshoot it further.