The remote host is missing an update to the system as announced in the referenced advisory.

Update your system with the appropriate patches or software upgrades. https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2011-4313 https://www.isc.org/software/bind/advisories/cve-2011-4313 http://www.vuxml.org/freebsd/90cc1494-10ac-11e1-b3ec-0024e830109b.html

The following packages are affected: bind96 bind97 bind98 CVE-2011-4313 query.c in ISC BIND 9.0.x through 9.6.x, 9.4-ESV through 9.4-ESV-R5, 9.6-ESV through 9.6-ESV-R5, 9.7.0 through 9.7.4, 9.8.0 through 9.8.1, and 9.9.0a1 through 9.9.0b1 allows remote attackers to cause a denial of service (assertion failure and named exit) via unknown vectors related to recursive DNS queries, error logging, and the caching of an invalid record by the resolver.