screen buffer overflow

Multiple unspecified vulnerabilities in the "utf8 combining characters handling" (utf8_handle_comb function in encoding.c) in screen before 4.0.3 allows user-assisted attackers to cause a denial of service (crash or hang) via certain UTF8 sequences.

GNU screen 4.0.3 allows local users to unlock the screen via a CTRL-C sequence at the password prompt. NOTE: multiple third parties report inability to reproduce this issue

screen: Unsafe usage of temporary file

GNU screen 4.0.3 creates the /tmp/screen-exchange temporary file with world-readable permissions, which might allow local users to obtain sensitive session information.

Buffer overflow in the Braille module for GNU screen 3.9.11, when HAVE_BRAILLE is defined, allows local users to execute arbitrary code.

security flaw

Integer signedness error in ansi.c for GNU screen 4.0.1 and earlier, and 3.9.15 and earlier, allows local users to execute arbitrary code via a large number of ";" (semicolon) characters in escape sequences, which leads to a buffer overflow.

Screen 5.0.0 and older versions allow file existence tests when installed setuid-root

A minor information leak when running Screen with setuid-root privileges allows unprivileged users to deduce information about a path that would otherwise not be available. Affected are older Screen versions, as well as version 5.0.0.

Temporary chown() of users' TTY to mode 0666 allows PTY hijacking in screen

For a short time they PTY is set to mode 666, allowing any user on the system to connect to the screen session.

Screen creates by default world-writable PTYs

The default mode of pseudo terminals (PTYs) allocated by Screen was changed from 0620 to 0622, thereby allowing anyone to write to any Screen PTYs in the system.

screen: allows sending SIGHUP to arbitrary PIDs

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.

screen: crash when processing combining chars

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.

screen: Privilege escalation via unsafe logfile handling

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.

screen: Out of bounds access when setting w_xtermosc after OSC 49

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.