The remote host is missing an update to xml-security-c announced via advisory DSA 1849-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%201849-1

It was discovered that the W3C XML Signature recommendation contains a protocol-level vulnerability related to HMAC output truncation. This update implements the proposed workaround in the C++ version of the Apache implementation of this standard, xml-security-c, by preventing truncation to output strings shorter than 80 bits or half of the original HMAC output, whichever is greater. For the old stable distribution (etch), this problem has been fixed in version 1.2.1-3+etch1. For the stable distribution (lenny), this problem has been fixed in version 1.4.0-3+lenny2. For the unstable distribution (sid), this problem has been fixed in version 1.4.0-4. We recommend that you upgrade your xml-security-c packages.