From
"Clam AntiVirus is a GPL anti-virus toolkit for UNIX. The main purpose of this software is the integration with mail servers (attachment scanning). The package provides a flexible and scalable multi-threaded daemon, a command line scanner, and a tool for automatic updating via Internet. The programs are based on a shared library distributed with the Clam AntiVirus package, which you can use with your own software. Most importantly, the virus database is kept up to date."
Certain types of RAR archives, including those created by variants of the W32.Beagle.A@mm worm, may cause clamav to crash when it attempts to process them.
This vulnerability causes a Denial of Service in the clamav process. Depending on configuration, this may cause dependent services such as mail to fail as well.
A workaround is not currently known for this issue. All users are advised to upgrade to the latest version of the affected package.
ClamAV users should upgrade to version 0.68.1 or later:
# emerge sync
# emerge -pv ">=app-antivirus/clamav-0.68.1"
# emerge ">=app-antivirus/clamav-0.68.1"