Cisco IOS 15.2(04)M and 15.4(03)M lets physical-interface ACLs supersede virtual PPP interface ACLs, which allows remote authenticated users to bypass intended network-traffic restrictions in opportunistic circumstances by using PPP, aka Bug ID CSCur61303.
http://www.securitytracker.com/id/1034158
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20151112-ios1