ClamAV is an antivirus toolkit. It includes a multi-threaded daemon and a command line scanner.
ClamAV fails to properly scan ZIP files with special headers (CAN-2005-0133) and base64 encoded images in URLs.
By sending a base64 encoded image file in a URL an attacker could evade virus scanning. By sending a specially-crafted ZIP file an attacker could cause a Denial of Service by crashing the clamd daemon.
There is no known workaround at this time.
All ClamAV users should upgrade to the latest version:
# emerge --sync # emerge --ask --oneshot --verbose ">=app-antivirus/clamav-0.81"