The remote host is missing an update to apr announced via advisory DSA 2237-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202237-1

A flaw was found in the APR library, which could be exploited through Apache HTTPD's mod_autoindex. If a directory indexed by mod_autoindex contained files with sufficiently long names, a remote attacker could send a carefully crafted request which would cause excessive CPU usage. This could be used in a denial of service attack. For the oldstable distribution (lenny), this problem has been fixed in version 1.2.12-5+lenny3. For the stable distribution (squeeze), this problem has been fixed in version 1.4.2-6+squeeze1. For the testing distribution (wheezy), this problem will be fixed in version 1.4.4-1. For the unstable distribution (sid), this problem has been fixed in version 1.4.4-1. We recommend that you upgrade your apr packages and restart the