socket.c in GNU Screen through 4.9.0, when installed setuid or setgid (the default on platforms such as Arch Linux and FreeBSD), allows local users to send a privileged SIGHUP signal to any PID, causing a denial of service or disruption of the target process.
encoding.c in GNU Screen through 4.8.0 allows remote attackers to cause a denial of service (invalid write access and application crash) or possibly have unspecified other impact via a crafted UTF-8 character sequence.
A buffer overflow was found in the way GNU Screen before 4.8.0 treated the special escape OSC 49. Specially crafted output, or a special program, could corrupt memory and crash Screen or possibly have unspecified other impact.
GNU screen before 4.5.1 allows local users to modify arbitrary files and consequently gain root privileges by leveraging improper checking of logfile permissions.