The remote Debian host is missing a security-related update.
Yves Orton discovered a flaw in the rehashing code of Perl. This flaw could be exploited to carry out a denial of service attack against code that uses arbitrary user input as hash keys. Specifically an attacker could create a set of keys of a hash causing a denial of service via memory exhaustion.
Upgrade the perl and libapache2-mod-perl2 packages. For the stable distribution (squeeze), this problem has been fixed in version 5.10.1-17squeeze6 of perl. For the stable distribution (squeeze), this problem has been fixed in version 2.0.4-7+squeeze1 of libapache2-mod-perl2.