Clam AntiVirus is a free anti-virus toolkit for UNIX, designed especially for e-mail scanning on mail gateways.
iDefense reported an integer overflow vulnerability in the cli_scanpe() function when parsing Portable Executable (PE) files packed in the MEW format, that could be exploited to cause a heap-based buffer overflow (CVE-2007-6335). Toeroek Edwin reported an off-by-one error when decompressing MS-ZIP compressed CAB files (CVE-2007-6336). An unspecified vulnerability related to the bzip2 decompression algorithm has also been discovered (CVE-2007-6337).
A remote attacker could entice a user or automated system to scan a specially crafted file, possibly leading to the execution of arbitrary code with the privileges of the user running ClamAV (either a system user or the "clamav" user if clamd is compromised).
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-0.91.2-r1"