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