tmux is a terminal multiplexer.
A flaw in tmux’s handling of escape characters was discovered which may allow a buffer overflow.
A remote attacker could possibly execute arbitrary code with the privileges of the process, or cause a Denial of Service condition.
There is no known workaround at this time.
All tmux users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=app-misc/tmux-3.1c"