Clam AntiVirus is a GPL anti-virus toolkit, designed for integration with mail servers to perform attachment scanning. Clam AntiVirus also provides a command line scanner and a tool for fetching updates of the virus database.
Andrew Toller and Stefan Kanthak discovered that a flaw in libmspack's Quantum archive decompressor renders Clam AntiVirus vulnerable to a Denial of Service attack.
A remote attacker could exploit this vulnerability to cause a Denial of Service by sending a specially crafted Quantum archive to the server.
There is no known workaround at this time.
All Clam AntiVirus users should upgrade to the latest available version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=app-antivirus/clamav-0.86.1"