Apache XML Security Multiple Vulnerabilities

Multiple vulnerabilities have been identified in Apache XML Security, which can be exploited by malicious people to conduct spoofing attacks, cause a DoS (Denial of Service), and compromise an application using the library.

1. An error when processing certain XPointer expressions within the XML Signature Reference processing code can be exploited to cause a stack-based buffer overflow.
2. An error when processing the length of HMAC-based XML signatures can be exploited to cause a crash.
3. Another error when processing HMAC-based XML signatures can be exploited to spoof XML data. 
   Note: This vulnerability is caused due to the incomplete fix for CVE-2009-0217.
4. An error when processing PrefixList attributes can be exploited to cause a heap-based buffer overflow.

Successful exploitation of the vulnerabilities #1 and #4 may allow execution of arbitrary code.