The remote host is missing an update to apr-util announced via advisory DSA 1812-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%201812-1

Apr-util, the Apache Portable Runtime Utility library, is used by Apache 2.x, Subversion, and other applications. Two denial of service vulnerabilities have been found in apr-util: kcope discovered a flaw in the handling of internal XML entities in the apr_xml_* interface that can be exploited to use all available memory. This denial of service can be triggered remotely in the Apache mod_dav and mod_dav_svn modules. (No CVE id yet) Matthew Palmer discovered an underflow flaw in the apr_strmatch_precompile function that can be exploited to cause a daemon crash. The vulnerability can be triggered (1) remotely in mod_dav_svn for Apache if the SVNMasterURIdirective is in use, (2) remotely in mod_apreq2 for Apache or other applications using libapreq2, or (3) locally in Apache by a crafted .htaccess file. (CVE-2009-0023) Other exploit paths in other applications using apr-util may exist. If you use Apache, or if you use svnserve in standalone mode, you need to restart the services after you upgraded the libaprutil1 package. For the stable distribution (lenny), these problems have been fixed in version 1.2.12+dfsg-8+lenny2. The oldstable distribution (etch), these problems have been fixed in version 1.2.7+dfsg-2+etch2. For the testing distribution (squeeze) and the unstable distribution (sid), these problems will be fixed soon. We recommend that you upgrade your apr-util packages.