How to fix “Socket creation in UltraProbe…Permission denied” error when using nmap?

I have a pre-compiled nmap binary for Android that was working properly and without error in LineageOS 14.1. The phone is a One Plus One.

Since upgrading to Lineage 15.1 (Android 8), the specific error I get is:

Socket creation in UltraProbe* sendConnectScanProbe(UltraScanInfo, HostScanStats, u16, u8, u8): Permission denied (13). 

This is when nmap is run as the standard user, as root the phone becomes unresponsive and immediately crashes. I read somewhere over on SO that someone who was also attempting to open a socket was running into a permission issue as well, but successfully circumvented it by adding the user into these groups: aid_bt, aid_bt_net, aid_inet, aid_net_raw, aid_admin

It doesn’t seem like this version of LineageOS has either groupadd or usermod, so that solution doesn’t help me.

Did any changes occur between the two versions of Lineage that could cause this problem?
And how can I make nmap work again?