Ethereal is a feature rich network protocol analyzer.
There are multiple vulnerabilities in versions of Ethereal earlier than 0.10.9, including:
An attacker might be able to use these vulnerabilities to crash Ethereal, perform DoS by CPU and disk space utilization or even execute arbitrary code with the permissions of the user running Ethereal, which could be the root user.
For a temporary workaround you can disable all affected protocol dissectors by selecting Analyze->Enabled Protocols... and deselecting them from the list. However, it is strongly recommended to upgrade to the latest stable version.
All Ethereal users should upgrade to the latest version:
# emerge --sync # emerge --ask --oneshot --verbose ">=net-analyzer/ethereal-0.10.9"