The passprompt plugin in pppd in ppp before 2.5.2 mishandles privileges.
{ "availability": "No subscription required", "binaries": [ { "binary_name": "ppp", "binary_version": "2.5.2-1+1" }, { "binary_name": "ppp-dbgsym", "binary_version": "2.5.2-1+1" }, { "binary_name": "ppp-dev", "binary_version": "2.5.2-1+1" } ] }