This is a webapp that is intentionally vulnerable to CVE-2022-42889.
It uses an embedded Jetty server and Maven to start a servlet listening at port 8080 at URL \api. This endpoint accepts a URL parameter cmd. This is embedded between ${ and } and passed to the StringSubstitutor function; which inturn implements the StringLookupFactory.
The vulnerability exists because the StringLookupFactory includes interpolators that can be can be easily exploited if provided untrusted input. These are script, dns and url. They have been disabled by default since v1.10.0 coomons-text versions 1.5 and above till v1.10 are affected.
You can run this locally by executing this command:
mvn package exec:java
Note: The program listens on
0.0.0.0by default. So, don't run this while connected to a untrusted network.