The remote host is missing an update to apt announced via advisory DSA 1779-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%201779-1

Two vulnerabilities have been discovered in APT, the well-known dpkg frontend. The Common Vulnerabilities and Exposures project identifies the following problems: CVE-2009-1300 In time zones where daylight savings time occurs at midnight, the apt cron.daily script fails, stopping new security updates from being applied automatically. CVE-2009-1358 A repository that has been signed with an expired or revoked OpenPGP key would still be considered valid by APT. For the old stable distribution (etch), these problems have been fixed in version 0.6.46.4-0.1+etch1. For the stable distribution (lenny), these problems have been fixed in version 0.7.20.2+lenny1. For the unstable distribution (sid), these problems have been fixed in version 0.7.21. We recommend that you upgrade your apt package.