Apache Commons Configuration, a Java library providing a generic configuration
interface, performs variable interpolation, allowing properties to be
dynamically evaluated and expanded. Starting with version 2.4 and continuing
through 2.7, the set of default Lookup instances included interpolators that
could result in arbitrary code execution or contact with remote servers. These
lookups are: – script – execute expressions using the JVM script execution
engine (javax.script) – dns – resolve dns records – url – load values from
urls, including from remote server applications using the interpolation
defaults in the affected versions may be vulnerable to remote code execution or
unintentional contact with remote servers if untrusted configuration values are
used.

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