Mandriva Linux Security Advisory 2009-267 – A missing check for the recommended minimum length of the truncated form of HMAC-based XML signatures was found in xmlsec1 prior to 1.2.12. An attacker could use this flaw to create a specially-crafted XML file that forges an XML signature, allowing the attacker to bypass authentication that is based on the XML Signature specification. This update fixes this vulnerability.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/81924/MDVSA-2009-267.txt
Source: https://packetstormsecurity.com/files/81924/Mandriva-Linux-Security-Advisory-2009-267.html