tcpdump is a tool for capturing and inspecting network traffic.
mu-b from Digital Labs discovered that the return value of a snprintf() call is not properly checked before being used. This could lead to an integer overflow.
A remote attacker could send specially crafted BGP packets on a network being monitored with tcpdump, possibly resulting in the execution of arbitrary code with the privileges of the user running tcpdump, which is usually root.
There is no known workaround at this time.
All tcpdump users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=net-analyzer/tcpdump-3.9.5-r3"