The squidclamav_check_preview_handler function in squidclamav.c in SquidClamav 5.x before 5.8 and 6.x before 6.7 passes an unescaped URL to a system command call, which allows remote attackers to cause a denial of service (daemon crash) via a URL with certain characters, as demonstrated using %0D or %0A.

Multiple cross-site scripting (XSS) vulnerabilities in SquidClamav 5.x before 5.8 allow remote attackers to inject arbitrary web script or HTML via the (1) url, (2) virus, (3) source, or (4) user parameter to (a) clwarn.cgi, (b) clwarn.cgi.de_DE, (c) clwarn.cgi.en_EN, (d) clwarn.cgi.fr_FR, (e) clwarn.cgi.pt_BR, or (f) clwarn.cgi.ru_RU in cgi-bin/.