Apache Santuario XML Security for C++ (aka xml-security-c) before 1.7.1 does not properly validate length values, which allows remote attackers to cause a denial of service or bypass the CVE-2009-0217 protection mechanism and spoof a signature via crafted length values to the (1) compareBase64StringToRaw, (2) DSIGAlgorithmHandlerDefault, or (3) DSIGAlgorithmHandlerDefault::verify functions.

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; (6) Sun JDK and JRE Update 14 and earlier; (7) Microsoft .NET Framework 3.0 through 3.0 SP2, 3.5, and 4.0; 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.