Off-by-one error in the extracthalf function in dpkg-deb/extract.c in the dpkg-deb component in Debian dpkg 1.16.x before 1.16.17 and 1.17.x before 1.17.26 allows remote attackers to execute arbitrary code via the archive magic version number in an "old-style" Debian binary package, which triggers a stack-based buffer overflow.