The remote Debian host is missing a security-related update.
It was discovered that malicious web applications could use the Expression Language to bypass protections of a Security Manager as expressions were evaluated within a privileged code section.
Upgrade the tomcat7 packages. For the oldstable distribution (wheezy), this problem has been fixed in version 7.0.28-4+deb7u3. This update also provides fixes for CVE-2013-4444, CVE-2014-0075, CVE-2014-0099, CVE-2014-0227 and CVE-2014-0230, which were all fixed for the stable distribution (jessie) already. For the stable distribution (jessie), this problem has been fixed in version 7.0.56-3+deb8u1.