From the CVE entry: The design of the W3C XML Signature Syntax and Processing (XMLDsig) recommendation, as implemented in products including (1) the Oracle Security Developer Tools component in Oracle Application Server 10.1.2.3, 10.1.3.4, and 10.1.4.3IM; (2) the WebLogic Server component in BEA Product Suite 10.3, 10.0 MP1, 9.2 MP3, 9.1, 9.0, and 8.1 SP6; (3) Mono before 2.4.2.2; (4) XML Security Library before 1.2.12; (5) IBM WebSphere Application Server Versions 6.0 through 6.0.2.33, 6.1 through 6.1.0.23, and 7.0 through 7.0.0.1; and other products uses a parameter that defines an HMAC truncation length (HMACOutputLength) but does not require a minimum for this length, which allows attackers to spoof HMAC-based signatures and bypass authentication by specifying a truncation length with a small number of bits.
