Xalan-Java is an XSLT processor for transforming XML documents into HTML, text, or other XML document types.
The TransformerFactory in Apache Xalan-Java does not properly restrict access to certain properties when FEATURE_SECURE_PROCESSING is enabled. This can also be exploited via a Java property that is bound to the XSLT 1.0 system-property function.
A remote attacker could inject specially crafted XSLT properties resulting in the execution of arbitrary code with the privileges of the process.
There is no known work around at this time.
All Xalan-Java users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=dev-java/xalan-2.7.2"