Clam AntiVirus (ClamAV) 0.88 and earlier allows remote attackers to cause a denial of service (crash) via a malformed base64-encoded MIME attachment that triggers a null pointer dereference.
http://www.securityfocus.com/bid/21510
http://www.novell.com/linux/security/advisories/2006_78_clamav.html
http://www.mandriva.com/security/advisories?name=MDKSA-2006:230
http://www.debian.org/security/2006/dsa-1232
http://secunia.com/advisories/23411