Wireshark is a network protocol analyzer with a graphical front-end.
Wireshark doesn't properly handle chunked encoding in HTTP responses (CVE-2007-3389), iSeries capture files (CVE-2007-3390), certain types of DCP ETSI packets (CVE-2007-3391), and SSL or MMS packets (CVE-2007-3392). An off-by-one error has been discovered in the DHCP/BOOTP dissector when handling DHCP-over-DOCSIS packets (CVE-2007-3393).
A remote attacker could send specially crafted packets on a network being monitored with Wireshark, possibly resulting in the execution of arbitrary code with the privileges of the user running Wireshark which might be the root user, or a Denial of Service.
In order to prevent root compromise, take network captures with tcpdump and analyze them running Wireshark as a least privileged user.
All Wireshark users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=net-analyzer/wireshark-0.99.6"