A popular Java library has a serious vulnerability, discovered over nine months ago, that continues to put thousands of Java applications and servers at risk of remote code execution attacks.
The flaw is located in Apache Commons, a library that contains a widely used set of Java components maintained by the Apache Software Foundation. The library is used by default in multiple Java application servers and other products including Oracle WebLogic, IBM WebSphere, JBoss, Jenkins and OpenNMS.
The flaw is specifically in the Collections component of Apache Commons and stems from unsafe deserialization of Java objects. In programming languages, serialization is the process of converting data to a binary format for storing it in a file or memory, or for sending it over the network. Deserialization is the reverse of that process.